>>82440251
That's going to vary from person to person. The most general qualities are probably going to be things like kindness, empathy, and humor though. Beyond that, you're looking at more individual tastes.
Personally I don't like everyone, and I don't expect to be liked by everyone. But being open-minded and willing to bring different aspects of your personality to the fore depending on the person can go a long way. Talk about work with people who are more diligent, joke with people who like to fuck around, etc. It's often enough to let people talk about things they're interested in, rather than try to impress them, and you can work from there.
If you literally want the basics of not being repellent, unironically read How to Win Friends and Influence People by Dale Carnegie. It's old as fuck and the title sounds like some alpha influencer bullshit but everything he has to say is legit and still applies today.