Negotiated my first-ever offer and almost didn't — here's what actually moved the number

Got my first offer four months ago and almost signed it as-is because I didn't want to seem difficult. My roommate talked me into pushing back — just asked if there was flexibility, no ultimatum, no other offer to wave around. They came back with 11% more and an extra day of WFH. Nobody explains that the first offer is basically never the real ceiling, especially for entry level. Wish someone had told me that before three previous offers I just accepted.