Watch enough boxing and you'll witness many incredible rivalries. Though they have not yet fought, the most well-known feud today might be Manny Pacquiao-Floyd Mayweather.
Some rivalries are rooted in sportsmanship, and both fighters respect each other—like Arturo Gatti and Micky Ward, or Evander Holyfield and Riddick Bowe.
Then there are the ugly ones, the rivalries where there is genuine hate and animosity. The trilogy of fights between Marco Antonio Barrera and Erik Morales is a perfect example.
There's no manufactured hype around these matchups to sell pay-per-views or generate headlines.
Some people just don't like each other.
Go back through boxing history, and the sport is littered with these feuds. Some feature many of the same fighters, some are regional, some are outside the ring.
Which is the ugliest? It's not too difficult to figure out, and the rivalry remains mythical, even among fans who were too young to remember their last fight.
Let's jump into it. Here are boxing's 20 ugliest rivalries:
The two had polar opposite personalities and Zab Judah kept disrespecting Kostya Tszyu every chance he got.
That didn't turn out so well for him in the end.
This stemmed back to their days as amateurs when Lennox Lewis defeated Riddick Bowe in the super heavyweight finals in the 1988 Summer Olympics.
Bowe eventually became the heavyweight champion, but refused to give Lewis a mandatory title shot and threw his WBC belt in the trash. Lewis was named champ and went on to have a highly successful career.
You could tell the two didn't care for each other at all, and Ricky Hatton's fans lit into Floyd Mayweather when they made their pre-fight press tour stop in England.
The two began fighting as amateurs, and Evander Holyfield actually beat Mike Tyson to make the legendary 1984 U.S. Olympic boxing team, which went on to win nine gold medals.
The two were set to fight in an epic showdown, but Tyson went to prison for rape. They finally met in 1996, and Holyfield pulled off a stunning upset.
Then came the infamous "Bite Fight," when Tyson bit Holyfield's ear in their rematch. Tyson said he got upset because he was being repeatedly headbutted.
Holyfield and Tyson have reconciled, and even appeared together on Oprah.
Floyd Mayweather Sr. was his son's original trainer, but the two became estranged for an extended period of time and didn't hold back about their feelings towards one another.
At the time, it was both sad and disturbing. If you listened to both of them, you could tell they still loved each other, but both were extremely proud and weren't willing to budge.
Luckily, the two have reunited, and it's good to see them back together.
I suppose you could trace this back to Mike Tyson saying he wanted to eat Lennox Lewis' children (even though he had none). The two finally met long after Tyson's prime, but the hate grew, especially after a brawl broke out when the fight was officially announced.
Then when they finally met, Lewis walked right through him. Like many others, I was extremely happy to see it.
It's one thing to taunt an opponent, but Ricardo Mayorga took it overboard with Fernando Vargas, Oscar De La Hoya and now with Miguel Cotto.
For Mayorga, no one, or nothing, is out of bounds, and he's continued to do nothing but agitate the other fighters.
Want to get an entire country to hate you? Easy—throw their flag on the ground.
That's what Bernard Hopkins did while touring to promote his middleweight title fight in 2001 with Puerto Rican icon Felix Trinidad.
Their stop in Puerto Rico got dangerous after Hopkins threw the flag down and barely escaped being hurt by a mob of fans.
Roy Jones Jr. beat Bernard Hopkins early in his professional career, and Hopkins continued to chase him down as they became two of the sport's greatest fighters. Jones refused to budge and kept saying "60-40, 60-40," referring to the purse split.
Unfortunately, the rematch didn't happen until both were well past their primes.
Mayorga went after the Golden Boy quickly, attacking Oscar De La Hoya, his wife and late mother.
When they finally met, De La Hoya gave Mayorga a beating.
It wasn't so much the hatred between the two fighters as it was what their two fights represented.
Max Schmeling pulled off the upset in their first fight, but the American Joe Louis was under immense pressure in the rematch, which was built up to be a battle between America and freedom vs. Hitler and the Nazis.
Schmeling was just simply in the ring to fight, and had no animosity towards Louis. What's sad is that after losing the rematch, Schmeling basically became an outcast back home in Germany.
The two haven't spoken since their controversial 1987 bout, and their fans still passionately debate who truly won the fight.
What fueled the animosity here was two-fold: First, you had two fighters from completely different backgrounds.
Sugar Ray Leonard was the superstar, the heir apparent to Muhammad Ali as America's next great boxing icon and the one who everybody had loved since he was in the Olympics. Marvin Hagler was a blue-collar fighter and had to earn his way to the top.
Then, when it looked like Hagler had a shot with Leonard way before 1987, Sugar Ray stood in front of a crowd in Baltimore and said he would never give him that opportunity.
Many Mexican fight fans grew to hate Oscar De La Hoya even more after he beat the legend, Julio Cesar Chavez, twice. This remains a polarizing issue still—those who stay true to their roots versus those who are proud of their heritage but embrace America and its opportunities.
Chavez walked in with Fernando Vargas when he faced the Golden Boy in their title fight.
You can't tell me this isn't vicious, because I sit here and see it regularly. Floyd Mayweather's fans snap at even the slightest negative thing said about "Money," and Manny Pacquiao's fans will defend his every decision passionately as well.
Both fanbases think their fighter is the greatest of this generation, and both won't hesitate to light into the other side.
Oscar De La Hoya hadn't even given Fernando Vargas the time of day for years, and Vargas kept calling him out. The two finally agreed to fight, and Vargas kept claiming he was more Mexican than De La Hoya was.
When he was asked if he was worried about Vargas crossing the line to provoke him, De La Hoya at the time laughed and said he'd just call Vargas' parole officer, a crack at the legal issues Vargas was dealing with.
This was a regional thing for the two Mexican legends: Erik Morales was from Tijuana, and Marco Antonio Barrera from Mexico City. Morales claimed that Barrera acted as if he were part of a higher class.
The two staged one of boxing's best trilogies. Their first fight won Fight of the Year honors from Ring Magazine, and is considered one of the all-time greats. Before their final bout, both matter-of-factly said they had no desire to shake hands or have beers and become friends someday.
You don't see that often, but maybe that's partially what made their fights so incredible.
Bob Arum was Oscar De La Hoya's original promoter, but the two later split and De La Hoya drew criticism for an alleged anti-Semitic remark about Arum. They patched up their differences, and De La Hoya got into promoting and started his own company.
That has blossomed, but Golden Boy Promotions and Top Rank are now bitter rivals who have filed lawsuits against each other and are now at a standstill as they work together on potential mega-fights.
When it comes to boxing, both countries have produced countless talented fighters and world champions. The Felix Trinidad-Oscar De La Hoya fight set a pay-per-view record for non-heavyweights, a mark that stood until De La Hoya's fight with Floyd Mayweather Jr.
Puerto Ricans loved seeing Trinidad take down De La Hoya, but the rivalry was re-heated again when Mexico's Antonio Margarito beat Miguel Cotto in an incredible fight.
It's still one of the most sickening things in this country's history: Jack Johnson was not given a title shot because of his skin color, and then when he finally did win the title, the goal was to dethrone him. Johnson became even more hated because of his involvement with white women.
Everything about the treatment of Johnson smacked of racism, and to know that this country still hasn't pardoned him is mind-boggling.
Their trilogy is the gold standard by which every other is measured.
The two definitely hated each other—Muhammad Ali's taunts are considered racist by many, and something that hurt Joe Frazier long after the two had retired.