I'm really pissed off at my compsci professor, possibly unreasonably.
1. He greeted me as ma'am. Seriously, I am so obviously not ma'am age.
2. In class, even though he'd never seen me before in my life, when I raised my hand he didn't just flick over it and keep looking, he'd stare at me and sort of crane his neck looking around for someone else to call on. I've never met any professor who did that in quite the same way. It was a 400-person lecture hall and he had a very "no, not you, fuck you" way of doing it. Didn't call on any girls, either--there were lots of questions he asked, but he somehow managed not to call on any women. There were lots there.
3. When I approached him to discuss course details, having sent him an email he'd apparently read, which detailed my grades, background, etc. (including that I'd gotten over 100% in a light-intro course, designed to help people with the course I was trying to get enrolled in--and that I was one course away from a degree in pure math)... well, he expressed a lot of rather condescending doubt that I'd be able to solve the week's collection of four little programming problems in 7 hours. It took about one, and that was only due to clashes with the previous language I'd learned.
4. The CS students in general also kind of treated me like I was too stupid to talk to.
5. As previously discussed, it was an atmosphere where dudes felt like they could hit on girls the minute they saw them.
I know that these sound small, but really, the thing was the atmosphere. It just felt really gross. I've been in plenty of classes where the gender balance was way more skewed; heck, I've been in courses where the professor was making misogynistic and antisemitic jokes. I've taken other CS and engineering classes. I've sat through the culture shock in English classes, where people would openly rag on and maim mathematics, and dealt with the Autism Speaks people. I've been the only woman in the room.
And yet, despite this, there's never been another course I took at Berkeley where I felt quite so excluded and unwelcome. It just felt gross.