How to leave a bad impression

It seems lots of people and companies out there are trying hard to leave a bad impression. If you want to join their ranks, here are a few tips:

Don’t respond to inquiries. If someone calls or emails, free free to ignore.
Don’t say thank you. If someone buys a product from you or gives you a contact or anything, don’t bother saying thank you. That would be nice.
Keep pounding away with the same message. Send the same offer over and over, a couple of times of day if possible.
Solicit free advice. Ask around for all the free advice you can. After all, it’s just advice, right?
After you get your free advice, feel free to ignore it. Someone’s an expert but that doesn’t mean he/she knows what she/he is saying.
Cancel or change plans at the last minute. Your time is more valuable than anybody else’s.
Use foul language. If you are on Twitter, go ahead, drop an f-bomb or two.
Be crass, self-involved, self-promoting. It’s all about you.

My question is: how hard are you trying to leave a bad impression?