Talking to people. I moved to US from Russia when I was 15. It was a long time ago (in 97), but I still have a slight accent. My written English is great, I write stories and have always been one of the best at writing in HS and in college. My experience with spoken English is totally different. I never know what to say to people (I am also a borderline introvert, so not a bubbly talkative personality) and am afraid that I will say something incorrectly. The anxiety kicks in and I end up just saying a whole bunch of stupid shit that later makes me go "ughh, seriously? I said this? Way to be a moron, ughh." Which makes me not want to initiate conversations. I am 33 and still have a highly awkward interaction stage. When I am with my bf, he is a social genius and knows how to talk to anyone. I just stand next to him like a mute.
Another insecurity-
Both of my parents have PhD's in science. I have failed science multiple times and have zero inclinations towards it. My mother couldn't work in her field for security reasons (she was a biologist who worked with deadly viruses in Russia) and learned computers in about a year, so she is a computer programmer now. Ofcourse I have zero computer skills and that career is out of the question. I feel like I was robbed genetically and subconsciously it sucks. My parents never told me this, or pressured me into anything- its just the way I feel. I have a blue collar job which I love and which gives me joy (the pay is very decent for what I do), but deep inside its like "why the f those parents produced someone with zero life skills?"
Another insecurity: I have never had a motherly instinct. All my friends have kids by now, and I never wanted any at any period of my life. It makes me feel like there is something wrong with me because I look at babies and don't want one/find any joy out of seeing them. Doesn't help that we live in a baby obsessed society and I'm an only child, which means no grandkids for my mother, who loves guilt trips.
Finally- I am short. As in barely 5'1". Yes, its different for females, but trust me- when you are 33 and that short, people think you are a joke. Not to mention that I look much younger and people assume I'm a college kid, which totally discredits any authority whatsoever. Gets very old. I never had trouble dating or anything like that and don't really think I have a complex, but every time I am next to taller women I feel like a lawn gnome or something.