Groomsmen.

What’s more fun when you’re single then watching other people be extremely happy because they have found their soul mate?  Weddings are great when you’re single only if the Groomsmen (or Bridesmaids) are hot.  But even more importantly, (I know, what’s more important than hot groomsmen?) weddings are a good reality check to see if you’re ready.  If you experience panic and a sense of suffocation when the couple says “until death do us part,” it is probably a good idea to hold onto your single status a little while longer.  Plus, I enjoy being happy for my married friends.  If they can do it, so can I.  In the next decade.