This is a tough question because I don't know if the things I worried about applied to me as a guy or just applied to me because of my personal situation. Looking at specific humiliations/concerns:
1) I worried constantly that anyone would find out my mother was an alcoholic. Biggest, most all-consuming fear for me, because I couldn't hide it - it was external, rather than internal.
2) I was embarrassed to be seen helping my mother walk down the hall and out of the school after a meeting (she had troubles walking for health reasons unrelated to her drinking). It was in the middle of a class, so there weren't many people around, but having anyone see was really mortifying.
3) We were poor, and I got free lunch tickets which I was usually too embarrassed to retrieve because I didn't want my friends to know. One day, a helpful lunch monitor brought me the ticket I had "forgotten", and I had to accept it in front of my friends.
4) Having my sister's "rich friend" offer to buy her a new winter coat, which upset my sister. Someone telling a local church we were hard up and them bringing bags of groceries around at Thanksgiving (which we didn't need and which made my mother cry).
5) Telling my best friend that I was gay and had a crush on him, only for him to tell me he didn't feel the same way (but was proud of me for coming out). Made me extremely embarrassed and uncomfortable.
6) Worrying that my super conservative stepfather would kick me out if he knew I was gay. In fact, I worried more about how to tell my family than whether anyone at school thought I was gay or not. I never really got teased about seeming gay, though.
7) Instead, I got teased for being fat. I could handle the weird girl I didn't know telling me I had bigger breasts than her mother, or the jerk who called me a girl and then pretended he'd been talking to his friend across the hall. It hurt, but I could brush it off. Not so easy when my friends - people I thought *liked* me - didn't realize I was around the corner, out of sight, and said that if I ever became a parent I could do the nursing of the kids.
So... this doesn't sound like the entirely typical "get a sweet ride, a fixer-upper of a car" or "I hope that the popular girl likes me". But these were things that I worried about and was embarrassed by in my high school days. Concerns were mostly focused on perception of my family and interpersonal relationships, as well as some worries about body image/popularity thrown in there.
I hope you find this helpful in some way!
Edited to add: Sorry if this veered away from "things I worried about as a teenage guy" and into a top 10 "my most embarrassing moments". Maybe the examples highlight some of the kinds of things I was worried about, though.