This thread in AskWomen is full of stories by women who regretted the career choices they made.

Some of the highlights:

I got a degree in civil engineering and worked as a geotechnical engineer for 5-6 years. I HATED always being dirty. I couldn't keep my nails clean. Couldn't wear nice clothes. Had to be in inclement weather all the time. Had to wear safety hats and vests al the time. I couldn't be feminine at all.

 

Software Engineer. While I am competent at my job, I am not as 'into' it as my co-workers. I don't do pet projects at home, I don't research the latest trends or look for a new cool programming language to try out in my spare time. This means I treat my job very much as a 9-5 time punch (in my case, 7-3). I struggle to keep current in my field. I am not much interested in advancing (but that's also partly because I love my current hours and flexibility and the work/life balance it allows me). [...] tl:dr: Picked a STEM career because I thought I should, would have been so much happier being a librarian.

 

Fashion design. The fashion industry has crippled to almost non existant so i have difficulties in getting any work. Been unemployed for 500 days soon.

 

Fashion Merchandising. AKA RETAIL.

 

I taught preschool part time in college, then got my degree in Elementary Ed, got into a classroom full time and DEAR GOD I HATED IT.

 

I went to law school, passed the bar, then realized I didn't like being a lawyer. I regret it, but a lot of the reasons I didn't like it were due to personality changes of getting older, so I don't think that I could have predicted I'd feel that way. Now I own a piece of paper worth more than my house and work in a traditionally underpaid industry trying to dig myself out. Yay.