How quickly does a game have to hook you before you put it away?

[Reasonable]

I buy carefully and will almost never put a game down unless it's obvious I've made a huge mistake, so this almost never happens to me. Even if a game isn't great I'll normally plough through

I'm also interested in game design so that's part of the reason why I won't quite a game, too - just likes films you often learn more easily from the flaws than the perfection.