It's funny if a dignified, well dressed man slips on a banana skin but not so funny if a tramp does it. But what if the tramp fractures his skull, receives compensation from the shop that sold the banana, buys some fine clothes, gets drunk on champagne, slips on another banana skin, fractures his skull again, loses his short term memory and wakes up wondering where all the fine clothes came from? That could be pretty funny, if it was in a film and the tramp was played by almost anyone except Rob Schneider. It's all about context: it's funny if your kid has an imaginary friend, not so funny if your heart surgeon has one.
Use your skill and judgement to see if you can tell what's funny and what's not so funny in this quiz: