I'm not sure why some posts on this thread are perpetuating the myth that you are either pretty or intelligent.
I was lucky enough to be both in my late teens and twenties. Admittedly some people underestimated my intelligence because I liked to be pretty and glamorous, but I saw that as their problem not mine (and v useful when negotiating deals at work).
I've lost my looks now really thanks to heavy steroids that have bloated by face, and a neuromuscular condition that has mishapen it, but I don't really mind. I would hate far more to lose my mental faculties.
I had no idea people could go for a walk and think about nothing/what to cook for dinner! I think about all sorts, philosophy, politics, economics, art, music, nature...
In one way being intelligent made school a breeze ,but on the other hand I was frequently bored, and also never really had to learn to try at anything. Driving lessons were a revelation. I found driving so hard and gave up several times. Then had my son and realised I needed to drive and so persevered and it was such a shock to realise you can find a skill hard but still master it with practice.
I have found it very alienating at times. My first husband wasn't bright and I didn't notice it to begin with as I was mixing with very bright people at work. But once I went on maternity leave I remember this desperate thirst for intelligent conversation. And just mixing with his friends and family, I didn't think less of them for not being bright, they were lovely normal people, but I knew I was always holding some of myself back in conversation.