I've always found it strange that some video games show you the total amount of time that you've played it. This seems like an anti-achievement to me. "Congratulations! You've wasted 25 hours of your life driving this animated character around an imaginary environment!"
And if you buy a game through Steam, then Steam will helpfully track your wasted time for you, even if the game itself is tactful enough to conceal this statistic from you. However, the centralized, cross-game nature of steam suggests a possible improvement to this feature. What I'd like to see, next to Steam's "total hours played" statistic, is a suggestion for what you might have otherwise accomplished with that time, such as "you could have learned a foreign language" or "you could have written a short novel" or (if you really want to stick the knife in) "you could have helped prepare 100 meals for the homeless."
At the very least it would be a good temporary "feature" for April Fool's Day sometime.