Here's an easy opener for you guys.

Go get a beer at the bar. Look around and find the first group of people, walk up to them in a nonthreatening way, and invade their personal space with a big heartfelt "Cheers guys!" as if they are your long lost friends. As long as they're not true assholes or in a pissy mood, they will cheers you, especially other dudes. Then you say, "Why can't you just go up to people and cheers them?"

The most common responses I've gotten:

  • "You can!" And I just did!
  • "You just did that." I know, isn't that great?
  • "I don't know." Well, I just did, and it seems to have made your night better off, right?
  • They frown. "Oh what's wrong? You don't like being happy?" Then I cheers them again.

IOIs from this approach are about 90% for me after trying it on about 30 different sets. Keep in mind though that it is a lower risk opener. If they're not warm, back off and go up to another set and do it. You can now always go back to the first set and talk a bit more whenever you feel like it. Odds are that they'll be happier to talk to you if you demonstrate that you won't let their sour mood ruin your night.

Everyone is my friend. They just don't know it yet.