Sometimes, things just don't work out.
For whatever reason, they don't go the way you thought they would. And it might be time to accept Shinji Kagawa's Manchester United career falls into that category.
He's not the first.
Juan Sebastian Veron was considered one of the best players in the world when he moved to Old Trafford from Lazio in 2001. But you'll find few United fans who consider his two years in a United shirt a success.
Chelsea supporters would say the same about Andriy Shevchenko's spell at Stamford Bridge.
Veron and Shevchenko were both fine players. Two of the best on the planet in their day. But they were considered failures in England.
There's a danger Kagawa's time in the Premier League will be remembered the same way.
Had things been different, Veron, Shevchenko and Kagawa might all have made successes of themselves.
If they had better adapted to the systems they were asked to play in or faced less competition in their favoured positions they might have thrived.
Maybe if they'd arrived in England earlier in their careers. Or even later.
Kagawa is still hopeful he can win a regular place in the United team.
He told the Manchester Evening News he wants to use Japan's friendly with New Zealand on Wednesday to impress David Moyes.
Of course it is important for a player to continue getting games, but there is not much I can do about my situation.
It is something that I won’t be able to gain unless I am delivering results.
I can’t change the situation I’m in so to I want to turn it into something positive and do well.
I want to grow by overcoming such a big wall in front of me.
It is significant that it exists in the World Cup year. I will have to deliver results.
It's admirable that after such a disappointing season, Kagawa, who has started just seven Premier League games this season, is still saying the right things.
But he's only played once since Juan Mata's arrival from Chelsea in January and that was against Olympiacos when the Spaniard was cup-tied and Adnan Januzaj was left at home.
It's not that Kagawa is a poor player. Or even a bad signing. But more than 18 months after he joined from Borussia Dortmund, United fans have only even seen flashes of what he can do.
If Moyes doesn't envisage a change in Kagawa's situation next season, if he thinks he'll still be behind Mata and Januzaj in the pecking order, then it's best for everyone if he's allowed to leave.
Kagawa can play regular first-team football. Moyes can recoup a bit of cash to help sign a central midfielder.
If he does go, and they'll be no shortage of takers, many United fans will see it as a missed opportunity. Especially if Kagawa goes on to be successful elsewhere.
But sometimes, things just don't work out the way you expected.