I keep calling people Bud, I feel like that's a silly word to use but I just can't seem to stop saying it.
Why don't you want to call everyone Bud?
It feels bad every time I do so.
If you want to use nicknames to refer to people, it is fine as long as the other person is receptive. You shouldn't cringe at your behavior but rather be more accepting. It's okay to be yourself as long as it doesn't negatively affect others.
I only want friends that I can call Bud.
There's nothing wrong with Bud, it's not rude and it could even be considered a charming colloquialism.