Rocks Off was struck by a random thought the other day: How cool would it be if a rock star showed up at your birthday party?

It could happen any number of ways. Maybe a well-connected friend calls in a few favors. Maybe your party is in the same hotel where they're staying. Maybe a series of comic mishaps led you and your friends to accidentally kidnap said rock star, but he's cool with it and, in a zany turn of events, winds up calling you and your buddies up onstage at the concert that night. (Starring Seth Rogen, Jason Segal and Zack Galifianakis, coming summer 2011.)

Sounds awesome, right? Not so fast. We can think of a few musicians with whom it would be a total drag to party.

5. Sufjan Stevens: Indie-folk wunderkind Stevens would constantly be making comments relating to his spirituality, like "Is this dip organic? The chemicals in normal dip interfere with my Higher Power," and, "You know, your story reminds me of Jesus' parable of the poor widow." Then when anyone asks him to elaborate upon his religion, Stevens would say something evasive like, "Oh, I don't like to talk about it, people will think I'm preaching."

Then he'd break out a litter of rainbow-colored puppies, a couple of animatronic teddy bears and a dulcimer, and sing "Higher Power" carols until every last guest is gone.

4. Axl Rose: First of all, he'd show up four hours late. Then he'd throw a tantrum, probably break something of yours, most likely something expensive. Finally, he'd pick a fight with some of your friends, shouting boasts and threats and conveniently disappearing in a sea of bodyguards before any physical contact is made. Rose would last be spotted storming to his limo, ranting angrily about God knows what. Total time spent at your party: Eight minutes.

3. Taylor Swift: No one wants to babysit the innocent girl at a party. She wouldn't have any idea how to drink, so you would have to either teach her or risk her getting alcohol poisoning - or, worse yet, abstaining entirely, doing the wallflower thing off in a corner and making everyone feel self-conscious. You've got to make sure your scummier friends don't try to slip her roofies or feed her too much Everclear punch, and watch out for pick-up artists trying to confuse her into sleeping with them.

Nothing against Taylor, it's just that having the young and inexperienced at your party is generally a bad idea.