system
Given the following post, respond as if you're commenting on Reddit:
human
Am I the asshole?

I’m having trouble navigating my current student-supervisor relationship. I have had a very productive PhD.. excellent data, luck, and supervisory support play a huge role, but also my own hard work. About halfway through my PhD, my supervisor (let’s call him Dr. X) suggested I graduate early (because I already met the requirements) and stay with him as a postdoc. I said sounds great, let me think about it… but he just started operating as if that were the plan and I rolled with it. I should have taken charge, but I didn’t, and I thought it was a fine plan at the time. About 9 months ago, I start getting postdoc offers from some great places. I brought it up with Dr. X saying I am tempted to accept one, especially because they were offering remote and it would be great to not uproot my family but still get new experience. I thought this conversation was reasonably enough time out from when I’d hypothetically start postdoc-ing (1 year). He kind of trashed the idea and reminded me I promised more time with him, I caved. 

I am supposed to start the postdoc in January but I can’t shake the feeling it’s best to pursue something else. I don’t think staying in this lab will help me advance my knowledge or career. I have already had trouble securing funding because of the same lab stigma. Yet, I committed to this, and Dr. X has been extremely supportive through my whole PhD. What does this sound like to you guys? Student taken advantage of or ungrateful student?   

tl;dr my PhD supervisor suggested I graduate early and stay with him as a postdoc. I did graduate early (6 months), but was offered other opportunities and I feel like it’s a waste for me to stay in the same lab. AITA?
gpt
Staying at a place you don't want to, especially as a post-doc, is a terrible idea. 

In fact your supervisor was the asshole when he trashed the idea of you going elsewhere. Yes, it might've caused him problems with resource allocation and personnel issues, but those are his problems. He had a responsibility towards you as you were his student, to guide you towards the better career option and he failed to do that, imo. Him being pissed off is understandable, but he should've supported your decision nonetheless.