for the functionally useless self-promoter:
1) Be careful who you screw over. This is a relatively small community and you never know who is going to get promoted and where you may have to interact with them again.
2) Seniors aren’t stupid. They can see through you. Just because they don’t argue with you as you talk about how wonderful you are doesn’t mean that they agree with you. Also: the good ones hate having your nose up their ass.
3) Your coworkers can see through you too. Leadership isn’t just a title, you have to be able to actually lead a team and you can’t do that if your coworkers don’t respect you.
4) Saying you are really good at people may just mean that no one thinks you are worth investing the effort in correcting or smacking.