Some things are just better that you don't do or say in life here are a few of them:
1) High Five an old person. It's weird they just can't seem to grasp this simple concept. I once tried it with gramps and it just became very awkward.
2) Look at somebody's toe nails. Apparently a lot of people have trouble properly grooming their toes and it ends up being ridiculous to look at. Oh and sickening.
3) Date a girl/boy with a kid. Unless your ready to be parent and truly understand all the baggage that entails (you don't) than your better off just staying away because dating somebody with a child will always put you number 2 when you want to be numero uno.
4) Asking somebody after a funeral who there doing. There is no optimistic answer that can be thought of so saying I send my condolences and I am sorry to hear seem to be most appropriate.