I have recently come back to playing chess. I find I do better, at least initially, when I am agressive and try to force my opponent to respond to me. Is agression a good chess strategy? If you control the board, won't you usually win?

Yes. Controlling the board and taking an offensive position is often better, however if your opponent plays defensively it then becomes a game of you trying to break their defense and they blocking attacks and looking to set traps or break out and checkmate you.

That's the fun of chess. :D

The main goal in chess is to achieve a superior attacking force that cannot be warded off. It is important to note that there is a difference between forceful, meaningful moves and just blind agression. You always want to maximize the force that your pieces exert (or limit that of your opponent), but it must be tempered with sound principles. An example of this is in boxing. A haymaker may be a very dynamic, agressive, and powerful blow, but an economical, well placed jab to the chin may strike with more affect.

Aggresion by itself isn't good.  Well calculated, timed and controlled agression on the other hand is unstoppable against most mortals. 

What we are really talking about is just semantics though.  Play good moves whether "agressive" "positional" or otherwise.