Pets

Pets. Although that can be used in a good way, they can also be used in a bad way.

Cuteness. Don't make a super cute pet that is just along for the ride. Make them actually have a use.

Don't do a cute animal like kitty, puppy, bunny or anything that's small and babyish unless it's like a lizard or parakeet that can be on your person.

For my example, I have a character with a huge owl and has a high tech mask. It's cool. Do a tiger or something cool and awesome. Not something cute and lame. Unless that character doesn't serve a purpose other than just an accessory.