Reading this thread and wanting to answer each post.
don't design games, MAKE games
There is a reverse problem too.
"don't program games, DESIGN games"
Programmers, who are capable of developing massive projects from ground up, usually struggle with design and end up making a game that is boring to everyone, including themselves. The problem is that they end up treating game design like programming i.e. coming up with coding challenges rather than thinking of things that will be fun to players.
I experienced both pitfalls myself. Really bad shit.
After playing Travian and Tribal Wars. I thought I can do it better.
Yes! That's another pitfall: to treat game design like you treat application development.
Basically, what I do when making games today is say to myself that "I can do this in a different way" rather than "I can do this better". Of course, there are some things that you can do better (like, game balance) but generally it's not enough to make you stand out from the crowd.