Position plays an important role in Texas Hold'em. Being first to bet puts you at a disadvantage. You are placing your bet without the added benefit of knowing what the other players are doing. Because of this, it is much harder to safely play marginal hands from first or second bet. It even makes playing good hands more difficult.
Many people will say that the button is the best position. I would agree most of the time. However, there is something alluring about being in one of the blind positions. If no one raises, you get a free or relatively cheap bet, and no one knows the strength of your hand. Even if you have something you wouldn't normally put money on, oftentimes, because other players assume you don't have anything, you can limp through the preflop with the chance of not only getting something on the flop, but also, being in a position to confuse your opponent. Have a good hand to begin with? Underbet and see if you can pull out a bigger pot. Have mid-trips after the flop? This hand is exceptionally good if another player hits top pair and mid or low pair (for two pair). You can even play this with low trips, however, I tend to get scared out of the bigger pots. Someone with two pair will normally go to the river or further (depending on how much you push). As long as you have the only trips (maybe with your pocket deuces) you're set.
Position is also helpful when bluffing. If you go through two other opponents' checks, why not throw on a bluff if you think you can get one or both of them to fold? Maybe you don't have top anything, but if you have a good number of outs, it tends to be worth it. Limit the competition, or get rid of it altogether and make the blinds plus a couple bets as well.