Valid reasons, but quick search for "option", "stock", "shares" did not find anything in that post - strange.
OP got stuck on low-end work and wasn't learning anything. She got shitty reviews. That doesn't mean she did a bad job or is incompetent (I doubt either is true) but it means they didn't value her, and she made the right call by getting out. If she'd stayed just to vest a few hundred shares of MSFT-- I doubt this benefit rang out to more than $10k per year-- she'd be nuts.
For example, if market is $125k, and you're making $100k + 0.2% of a company worth $100M, that's:
Equity is worth 200k over 4 years, or 50k/year. (40% of market salary.)
-20 (paycut) + 40 = 20
Below 0: Fucking awful. They don't respect you. Leave.
0 to 25: Mediocre, not interesting. OK for an otherwise attractive job.
25 to 60: Substantial but probably not life-changing equity. Typical for good contributors.
60 to 200: Real equity. They want you. They care if you work there.
200+: Founder-level.