Lack of compassion.

Aside from the usual suspects (e.g., the Seven Deadly Sins) I tend to have a malfunction with incuriosity. I'm not saying people have to be curious about the same things I am, to the same degree, but if nothing in life interests them enough to closely observe and learn all they can about it, in my experience, they tend to be easily influenced / led by others or by their own myopias, and to be very un self-aware. Which allows someone to have greed, envy, pride, wrath, etc., much more readily. One, you can't see it in yourself, and two, you aren't sufficiently committed to reality to want to have any fidelity to it ... so it's easy to lie, cheat, and steal, almost without even trying. If there's anything worse than a bad actor, it's a bad actor who thinks he's a good, even virtuous, actor.

And as a practical matter if you don't find life interesting you'll be much more prone to depression, boredom, etc.

I always think of the title of Richard Feynman's book, The Pleasure of Finding Things Out. He's my role model in this regard.

To be curious, one has to have intellectual freedom and has to grow up around people who value it. My father didn't finish the 6th grade but was enough of an autodidact to be an accomplished and respected aircraft mechanic and instrument-rated pilot. He learned math and passed tests that are over my head. My mother was at least indifferent to such things but I think I owe my curiosity to my father and to two of my three brothers. In particular one of my brothers did something that just Wasn't Done in our family, he started a business. That gave me "permission" to consider that an option for myself. I've been happily self-employed all my life -- because my brother inspired me, thanks to his willingness to be curious about other ways of being.

Curiosity is also a recognized marker of intelligence. In my view you don't have to be smart to be curious; being curious makes you smart.

Lying, followed by stupidity

Willful ignorance

Belief in their own "little white lies."

Pent Up suicidal aggression..

Keeping the list running.. I’m adding pettiness. Petty people drive me crazy as well.

Deceit

Inconsideration

Chosen ignorance.

not knowing when to stop talking - especiallly when i'm working

List is pretty good so far....I would add hypocrisy.

I dislike the trait of being judgmental - in addition to the traits already mentioned.

(I know I'm being judgmental by judging those who are judgmental, but you did ask what trait I dislike in OTHERS, not myself!)

I guess tribalism is the umbrella term, made up of all its precipitating factors: fear, anger, ignorance, a combative degree of insulated conservatism and jingoism, narcissism, solipsism, anything that puts you in a tenable corner on the wrong end of the Dunning-kreuger effect with a red hat on.

Cruelty.

Critical behavior and lack of empathy.

Blatant dishonesty.

I have problems when people never stop talking. I know some very nice very knowledgeable people who have this issue. One is quite knowledgeable but when you ask him what time it is, he tells you how to build a clock.