Equal treatment can sometimes breed resentment
Want to earn a lot of bad feelings from insecure people? Treat them as equals.
I hope you just read that and thought, "wait, what?" ... I will explain.
First, let's assume you're really good at something without really realizing it. Maybe you have some kind of double-jointed craziness going on in your hands combined with some particularly fast twitchy muscle pairing. This lets you push buttons on a gaming controller in a certain rhythm that most people cannot do. This makes you unstoppable in certain types of video games.
A few people in your life have watched you play, and as you stared at the screen, they saw what your hands were doing. They knew they had never seen anything like it before, and told you that. You, however, for whatever reason, default to not believing them. You genuinely think that you are just an average person when it comes to most things, and you certainly aren't anything special in this realm. After all, there's this person who did X, and that guy who did Y, and all of these other super gamers out there, and you're just you.
A new game in a popular series comes out, and it's a 4 player thing. You team up with 3 other people and start playing. There's some big monster coming up, and you can't take it on alone. The others on your team have to do their part and plug away at the thing, too. It requires a whole bunch of fast twitching and button smashing and precise timing of combinations.
You're managing to nail the combos, but your teammates aren't. They ask for help and you just say "do A+B then X+Z then X+Y!", and that's the truth, but it turns out they are physically unable to do that sort of thing. For whatever reason, most people's hands can't move that precisely and quickly, and they can't trip the combo. Your team gets slaughtered by the monster.
Afterward, you get to talking with the others. They ask how you are supposed to get past the monster, and you tell them the sequence again. This is the point where reality diverges. You are operating on the assumption they are able to do it, since, well, you can do it, and you're nobody special, and they should be at least as good as you if not better. After all, they were playing these games long before you showed up. You're the newest member of the team.
Meanwhile, all they hear you saying is "do (some impossible thing)". They figure you're doing it on purpose, as if to say "look what I can do". They think you're showing off. You aren't, but they don't realize this. You also think they are fully capable of doing what it takes to make this work.
Things only go downhill from here. They think you're trying to make them look stupid or broken or whatever, and you're only trying to treat them as peers, or even as better than you. It's just the way your internal value system works. After all, it would be presumptuous to think you were the best player around, so you don't.
The people who can't handle this eventually cause the team to fracture. They go one way and you go another. If you're lucky, you eventually find people who are also able to do the same funky twitch combo magic while gaming, or at least find some friends who aren't threatened by your ability to do them. Then you can go off and slay the monster at last.
Of course, if you aren't lucky, you might keep running into this, and that monster may never go away... all because you treated them as equals and they couldn't handle it.