Shows up late for a meeting. If someone is kind enough to meet with you, be there early. I would always try to get to a meeting 20-30 minutes early, so I could make sure I was ready to go at the time of my appointment.
Is disrespectful to anyone that gives you critiques of your work. Again, if someone is kind enough to take the time to listen, thank them and be polite even if you disagree with their opinion.
Continually complains about the music business or the music on the radio. If you hate it, then do something else. Why try to be a part of something you despise? Plus, the people who are succeeding aren’t complaining, so complaining about it just lets everyone know that you are not succeeding. Be positive. Work hard. Write the best songs you can write and continually get better. That will take you a lot farther than complaining will.
Holds a grudge. Keeping a list of people that rejected you and throwing it in their face once you do succeed is only going to hurt you in the end. I had people who wouldn’t sign me calling to ask me to write with their writers once I had some hits. Being a jerk to them would have hurt my career. It’s a small town. It’s best just to suck it up, treat them nicely and take every good opportunity you get. Holding a grudge doesn’t hurt the other person – only you!
Plays their songs around town too early. Unless you have 10 or more cuttable songs, you don’t need a publisher or a song plugger. Going all over town playing your songs for people before that point burns bridges. You have to understand how the game works and people want to work with writers who have a catalog of great songs, not just one or two. Spend your time writing more great songs before you play them all over town.
“That guy” gets a bad reputation. That’s not what you want.