What would make you stop playing games?

So, had my first exam of the Summer 2010 season the other day. Went pretty alright, I think, and the paper seemed very easy. Got the second one tomorrow - "Programming Techniques and Logical Methods". Hopefully won't be too bad. Really, really, really would love to get an A in it, so up a bit earlier tomorrow to do some quick last-minute revision. 
 
Anyways, the point of this blog. I've been in secondary school for 7 years now, and it's my last year at sixth form, doing my A2 levels. I have never felt this much stress/anxiety over the exams. This time, it really feels like I need to put in a lot of effort - and I have done. I'd love to get the grades I need for University in September, and will be devastated if I don't. 
 
I've even stopped playing games. 
 
What would make you to stop playing games?