Awwww quite a few of these, but some off the top of my head.
Rudeness
It’s in many forms, from ignoring someone who bothers with you, to being snappy or generally rude to someone for no reason.
Disrespect
*Especially when people act appallingly to people who are in the service industry. Just because someone is in a job where they are doing something for you, does not mean they are less than you, I can’t tell you how many times I had people clicking their fingers at me whilst I was a waitress, damn I wanted to break their bloody fingers.
And when people are just rude or snappy to shop assistants, delivery drivers, waiters, bar staff etc, it gets on my last god damn nerve.
People who walk past and don’t help others.
I can’t believe some people see others struggling or needing help and just stroll on by. I can’t do it. Maybe because I am used to helping when someone needs it or perhaps it’s just the way I was brought up, but I hate to think of someone struggling and being left to it. I even left my shift once to go outside and help an old man put his backpack up onto his shoulders again 
When someone has a conversation right in front of me, with someone that they know, and they don’t bother to introduce us.
IT’S AWKWARD!!! It takes 2 seconds to say something like, “I’d like you to meet …” So please just do it and don’t leave someone standing there like a spare part at a wedding.
Chewing with your mouth open.
Does this really even need to be brought up? You learn to eat as a kid, you shut your mouth when you aren’t talking, so combine the two… easy!
Over the top hand/head gestures.
If ever you’ve seen on tv, or in reality, there’s those people who think they are so cool and so tough that they have a blazing row with another idiot and both are getting all in each other’s faces, they start swinging their arms around like a music conductor caught in a windmill and bouncing their head all over the place and side to side at them. Oh dear, I just wanna hit them with a truck.
People saying you shouldn’t help the people on the streets.
You’re being an asshole, I’m helping, end of story 
Lack of loyalty
Friend or family, you care about someone, be loyal to them, if you can’t be, then don’t claim to care about them.
Oh there are so many more, but I think I will leave it here 