Take Offense If an Artist Doesn't Want to Do Your Tattoo. It means their style of tattooing doesn't fit your tattoo. Or, it could mean your tattoo idea sucks, honestly.
Tribal? I'm sure there isn't a tattoo artist in the world that likes tribal. It's 20 years ago, so please, don't get any. You'll be turned down by every decent shop you go into, because tribal sucks.
An entire song on your ribs? Probably going to get turned down, too. We are artists; we create art, not fill up our canvas with words. And yes, artists do specialize in a style of tattooing.
At my shop, for example, we have a traditional guy, a portrait guy, a realism guy (who also does neotraditional) and me -- I'm, um, artsy-fartsy, I guess.
I do a lot of flowers and girly stuff, but I love to do coverups. So, if you want to be tattooed by me, but you want a traditional piece, I'm gonna send you to the traditional guy; it's just how I am.