I've not been involved in any leadership roles because I've never thought to apply really, never wanted that from my career so far, but I've been involved in roles where I've been a trainer/the most experienced in a team. When I think about leadership I think about the worst bosses I've had, the middle of the road and the best.
The worst have without doubt had no people skills whatsoever, just been really good at their job and are really productive but can talk to you like shit in an instant. The middle of the road bosses have been easy to work with, not stressful but also don't really get things done/seem to linger with your development. I would say in my working life so far, and all the jobs I've done, I've probably had 2 absolute genuinely great bosses and a couple after that, that are up there but not the best I've had. The main points about their leadership though is this: they're extremely honest and don't lead you on, they're genuinely interested in your life and you as a person (had one boss that went out of his way to essentially say good morning/good afternoon/have a chat with close to 100 people every day, because he genuinely wanted people to feel like the workplace was a good place to be), they treat you like adults, tell you what you're doing wrong as it needs to be said in a calm and concise way and have an action plan for you to turn it around...essentially they're not like a teacher with students, because some bosses can be really patronising and will talk down to you without you realising it.