HAHA! Havne't we all wanted to do this at least once?!
I have a harder time not having cart rage in Walmart though! Once, I purposely went around an isle just so I could get in front of an a-hole and be in their way. Spend about 15 min staying in front of them and getting in the way. I won't say it actually felt good or anything, I saw it as the only way to show the person what they were doing to others. It didn't seem to help though. After several failed attempts to get by me they rudely said "excuse me!" so I rudely gave them just enough room to get by and then went straight to the checkout and left.
Some people will just never learn no matter how nice or mean you are to them.