I don't like being a jerk, however being a jerk is different than being assertive and standing up for yourself.
If a person is walking all over you or puts you in a position where you are being wronged, I see no shame in telling them to go screw off (or whatever else is appropriate action to get them to stop).
I don't particularly find joy in situations where an individual "had it coming" and "got what they deserved", for example, if a high ranking CEO were to go and mouth off on Twitter their controversial personal beliefs, the words get passed all over the internet and this person finds themself neck deep in death threads and possibly a ruined career, all because they made one stupid mistake.[footnote] this is a general scenario, there are specific versions, but I have no desire to bring them up[/footnote]
Being nice to people IMO is more effective. If someone is just angry, being kind can help calm that anger (or at least turn it in a direction that's not at you), if they're being a bully and just trying to piss you off, nothing makes a better reversal than showing them it's not working.
"Smile, you'll either fill their heart with joy or piss them off, either way, you win."
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As for the question, I'm sure some people find being a jerk empowering, otherwise there wouldn't be so many jerks. Some people find poking fun at others makes them feel better about their own shortcomings. I'm not immune to this behavior, but if I catch myself doing it, I tend to feel bad about it afterward.
If my years spent in retail have anything to say for it, there are people though, who seem to be jerks 24/7, rare, miserable individuals who must take some form of joy out of it, otherwise why would they keep doing it? I don't think I'd want to live their life, since I wonder what must have happened to them to make them that way.