Of course, so did some of his most disappointing moments in professional baseball.
On balance, though, Halladay's highest highs will be treasured long after the ugly images of his lowest Phillies lows are airbrushed out of memory.
Some Phillies fans will point to Halladay's May 29, 2010, perfect game against the Florida Marlins as the apex of his Phillies career. After all, how can you do better than 27 up, 27 down?
That the perfect game came during Halladay's Cy Young 2010 season only adds to its luster.
But perfect games, rare as they are, happen far more often than what Halladay did in the 2010 postseason.
On October 6, 2010, Halladay threw a no-hitter in Game One of the Phillies' National League Division Series against the Cincinnati Reds, the second playoff no-hitter in baseball history.
As recounted by Todd Zolecki in his game story for MLB.com, the no-no dented the record books on numerous levels:
Halladay is just the fifth pitcher to throw two no-hitters in the same season, but the first to throw one in his first postseason start. Halladay is also the first pitcher to throw a no-hitter and a perfect game in the same season.
The moment Phillies catcher Carlos Ruiz threw Brandon Phillips out to complete the feat, Phillies fans surely thought it could never get better.
They were right.
As set forth by Michael Baumann of Grantland, "That moment was the high point. Halladay split a pair of decisions with Tim Lincecum in the NLCS the next week, then a year later, allowed the first batter he faced to score in the deciding game of the NLDS against St. Louis."
Baumann's coda on that paragraph—"We didn’t know it at the time, but Halladay would never be Halladay again"—stings the Phillies fan in both its accuracy and finality.
After all the good, Phillies fans probably had to expect and accept some bad and even some ugly, which is more or less all Halladay had to give in 2013.
It was bad when Halladay threw a pitch behind reserve Washington Nationals outfielder Tyler Moore in an early 2013 spring training game.
What was Halladay's greatest Phillies performance?
It was ugly when Halladay gave up nine earned runs after getting only seven outs against an offensively challenged Miami Marlins lineup.
And little could be uglier than the realization that the Phillies paid Halladay $20 million in 2013 to go 4-5 with an earned run average just under seven in 13 starts.
Then again, maybe Halladay's inability to deliver value on the last year of his contract was a really well-disguised blessing because, ultimately, Roy Halladay did something harder than throwing a perfect game or a postseason no-hitter: He walked away before he was told to go home.
As a result, Phillies fans (and Blue Jays fans too) will be spared the sort of disappointment that denial-afflicted greats like Steve Carlton inflicted on their legacies by hanging on too long.
"To go out there and know it's not going to feel good and I wasn't going to do it the way I wanted was frustrating," Halladay said at his retirement press conference. "I tried to give everything I can but something was holding me back. I felt I couldn't give them what I wanted to."
Even in admitting the end, then, Halladay approached the perfection for which he was known.