You don’t have that many responsibilities. Play good defense. Drain your free-throws. But don’t turn the ball over and don’t botch the job. So while, in general, we advocate blowing off the silly stuff, it’s critical that you don’t flub your basic assignments.
In addition to all of your “soft” responsibilities like supporting your fiancée, navigating the treacherous waters of family politics, and collaborating on the big decisions like the budget, date, and venue, you will also have some very specific, concrete “groom duties.”