I got a chance to hit a local one last night. It's funny, the more I go to the ones out in the suburbs the more some things always seem to be true about them.
There's always a guy in his mid-to-late 50's in a Hawaiian shirt; he never drinks. He may have a Coke or some water, but he never ever touches an alcoholic beverage.
Just because there's a stupid brimmed hat being work does NOT mean an SRV devotee. However, if they have a Strat then it's a 98% chance you're going to add a "+1" to the number of times you've sat through "Pride and Joy."
The kid that comes up and starts doing whammy tricks is also almost just as likely to lay down a version of "Pride and Joy" after he's done slaughtering whatever it is he is "updating" with two-handed tapping and the like....and irrevocably tainting any positive memory you have of that specific tune.
If you can sing you will always get called up before anyone else. Even if you can sing badly you'll end up on stage as soon as possible without ruffling the feathers of those that signed up before you.
If you can sing adequately the odds are someone will try and recruit you for another jam or into a band.
If you play a 12 bar Blues tune and follow it with a Rolling Stones tune, and do them well, you can just about bet that any biker in the bar will stand in between a bullet and you for that night.