Interrupting people while they speak
Disadvantages:
Suggestion: Maybe you could practice active listening and wait for the speaker to finish before responding.
Chewing loudly
Leaving dirty dishes in the sink
Littering (throwing trash on streets)
Cracking knuckles loudly
Using a phone during conversations
Disadvantages:
Talking with your mouth full
Leaving empty containers in the fridge
Spitting on the ground
Tapping a pen or fingers constantly
Bragging too much.
Not washing hands after using the restroom
Leaving hair in the shower drain
Playing loud music in public
Snoring loudly
Gossiping about others.
Not using deodorant
Leaving lights on when leaving a room
Cutting in line
Being late all the time
Invading personal space
Not covering your mouth when coughing or sneezing
Not returning borrowed items
Talking too loudly on the phone
Forgetting to say "please" and "thank you"