I don't care if you prevent me from posting for 20 seconds, but if you make my laptop fan spin up, or cause my old computer to get unresponsive, especially if I have no clue why, I'm gonna be upset. I'm used to video sites slowing down the computer slightly, but if a simple blog does it, I'm gonna be confused, and possibly pissed.

I doubt that 100% CPU use for 20 seconds is going to make either of those things happen. Maybe reserve your anger for things that occur.