As someone on the hiring side, I strongly agree with GP.

I can think of a specific example where someone with experience and strong qualifications pushed for a higher salary - which I agreed to - then struggled with the role and ended up not sticking around. In another instance, someone had lower qualifications and experience, but also negotiated hardest out of their hiring cohort - same outcome, plus they weren't a great fit personality wise.

Meanwhile, I can think of several other people who cross-trained from their initial non-technical careers at the local community college, came in with low experience, didn't negotiate aggressively (although did stand up for themselves)... They've done great work (and grown substantially and been good to work with) over the long term, and seem to enjoy working for me enough that a few who left for other jobs were interested in being hired again later on.

Negotiating employment terms is the first task you complete at a new job. It is a good predictor. If it leaves a bad taste in the mouth for either side, it's not a good sign of things to come...