LoniceraJaponica
I know how to be polite and assertive, and how to humour people. I am not in the least bit confrontational, but I can get my point across if it differs from someone elses just by not being rude
So true. Shitty service doesn't happen to me too, for the reasons you named, and English isn't my first language. What you said earlier about assertiveness without being rude or aggressive is also a valuable skill, for a lot of people don't see the difference.
KindergartenKop
Patience - also a good one, I mean it as in "not snapping at people" however busy/stressed one can be. I used to smile and say, if someone came at a wrong moment, "Sorry, it's not a good moment. Can I talk to you in 20 min?" rather than snapping/barking at them. I think no amount of stress excuses snapping/rudeness. If you take too much on for promotion, it's your problem, not of the co-workers. If your workload is unreasonable, it's your call to talk to the manager about alleviating it.
HashTagLil
Learning how to admit I don’t know something, and ask questions
I think I didn't wait to learn it at work, just always done it. it's a good litmus test too: good people will answer the question, jumped-up morons will be "what, you don't know??"