That's one reason I like to play fast, some people play much worse as a result.
Anyway, no matter how fast or slow they're playing, remember the value of their move isn't changed. To win, even in speed games, your strategy is to make good use of your time. Try to have about half your time left around move 20 or 30. If you're going slower than that, then you can speed up. But don't speed up because your opponent is playing fast.
One thing about many fast players is -- they have trouble slowing down. So you might be worried they have many minutes left... but they probably wont use them. They will continue playing at a fast pace until the game ends. So the best thing to do is just pace yourself and ignore them.
Everytime i play someone that plays very fast i feel an urge to play as fast as he/she does. In these games i'll be more nervous and i make more mistakes than usual. Does anyone has this same issue? And if so, how do you deal with it?