Butch / Vince antagonism

Butch’s matches are televised and everything so Vince probably recognizes him. As to why that is, Vince is a pretty opinionated guy and likely looks down on bums who take a fall for the mob.

I think Vince naturally wants to show people he isn't intimidated by anyone and won't back down.

Even with the Wolf, he makes the point of not wanting the Wolf to boss him around. He wants to be asked not told. It's an indication that he wants to be the one in power and won't be bullied.

I think with Butch, he sees Butch and recognizes someone who prides himself as tough and a well known boxer. Vince stares at him to send the message "I'm not afraid of you".

Thus begins the lead up to an epic stare down.

Vince knew Butch was going to throw the fight and he didn’t respect that. That’s why he called him “palooka” and “punchy”

Also keep in mind that Vince has had a really bad day so that probably played a factor:

Vincent is a fucking moron, a well written character, but an imbecile nonetheless, he’s screwing up consistently throughout the entire film, so it’s not surprising that he is also emotionally immature, unable to manage his ego and oblivious to the fact that he’s a grade A fuck up.
He’s a ticking time bomb waiting to go off, I mean the man is in the throes of a mainlining heroin addiction while Butch is the polar opposite, intelligent, physically and emotionally controlled, focused and not intimidated in the least by Vincent, so naturally Vincent hates Butch the moment he see him, from a literary perspective they’re yin and yang….

To set up the scene later when Butch shoots Vincent with the gun.

Vince calls Butch, "punchy" which means a boxer who's been punched so many times, that they have brain damage, and a "palooka" which is an old, dated term for a bad or average boxer. I guess Vince just didn't like Butch's boxing career. He probably also didn't respect Butch's choice to throw the fight.

Vincent was just a jerk who felt his peace was being disturbed after everything HE caused that day, and was just projecting his issues onto Butch when he came to the counter. Vince sees everyone around him except for himself as a problem of disrespect to him. That's also why he's a jerk to the Wolf and why he disagrees with Jules's philosophy of "walking the earth".