1. Trying too hard and carrying on too long kills humor. There was a poster on this board (liberal bent) who would try to create their own satirical news articles but made them so long and so filled with zinging attempts that it ended up reading more like a screed than a piece of humor.
2. This same poster had the habit of trying to top any humorous or satirical post that popped up. It never works. You just end up seeming foolish.
3. There's no humor in poking fun at someone who suffers from autism. Nor is it very Christian, one might suggest.
So, if I encounter something amusing I want to share, I make sure it stands on its own and never post such material as an answer to another poost.