I'm someone who tends to get along and work well with others. That part definitely has its advantages for employability (and life in general), and is recommended. However, taking it to this extreme is just dangerous advice. Constantly being a people pleaser can carry enormous risks, especially (but not limited to) to yourself. It's important to learn to be ok with people disliking you sometimes.
I'd rather a teammate who is honest about their current limitations than someone who tells me what I want to hear. If someone admits they are stretched thin, it's now an "us versus the problem" to find why you are so overtasked. If someone consistently takes on too much (because they can't say no) and causes the team to miss deadlines, it's now an "us versus you" problem.
The most hated guy at my old job would start every request with an elaborate hand-wrung introduction to make sure no one could possibly be offended by what he was asking for.
Because of this, everyone had to read one or two paragraphs of niceties before they had any idea what he actually needed.
It was incredibly annoying and actually quite selfish in practice since it wasted so much time.
That sort of people pleasing behavior can easily come from a past where asserting even a minor need or boundary was met with abuse from caretakers or peers.
Not saying it's not maladaptive and irritating behavior. It is! But they probably came by it honestly.
I'd imagine if he was strictly an FTE he would have been getting that guidance and support, but I guess the politics of trying to do so across company boundaries made it too much of a career risk for the "manager" he was assigned from my company.
Edit: I'd maybe clarify that trying to get people above you not to dislike you is essentially the nature the politics of careerist ladder climbing. If you get laid off, it's just pretty common for people to see themselves as inherently superior because they weren't let go, and therefore think, right or wrong, that you'll reflect poorly on them, because they're careerist ladder climbers. So maybe it's best to carefully cultivate the people from the very start of meeting them which ones still have souls.