Yes. It stresses you out, first of all. I think the biggest problem is that everyone has their own algorithms for solving problems and your brain naturally goes with what seems natural when you see a problem. However, other people force their methods (which I'm sure work for some) on you, which could screw you up. You know yourself better than anyone else and I'm sure you're mature enough to make your own decision about what's best for your future. Personally, my test preparation involves doing nothing. It works for me. It probably wouldn't work [well] for most people, but that just goes to show how differently people's brains function.