@Anemone's comment "chasing a childhood that I didn't get first time around" resonates with me. In my little activities, I often try to do things I didn't experience for real, and as such as a child, I like to wear the casual clothes I
didn't wear as a kid. In fact, as an adult, I really dislike dressing formally, and only do so when I have to.
My parents tended to give me quite old-fashioned clothes; they themselves were older, and had older parents, and used hand-me-downs as much as they could rather than new clothes. Also, as a child, I simply wasn't interested in clothes, and never asked for particular ones, and I think I probably did suffer at school because of it, without knowing at the time. I don't wear girls' clothes out and about, but I do lament the lack of variety in menswear. Some of the casual clothes I like to wear now which I didn't back in the day are:
- Character T-shirts; I hardly had any as a child, and I most often had buttoned shirts with a collar, even in summer.
- Anoraks: my childhood outerwear was usually a duffle coat with toggles, as worn by Paddington Bear. Never again will I wear one. I dislike wellies for the same reason; now I prefer walking boots.
- Sportswear: I wasn't into sport at all as a child or teenager, but I love wearing it now, whether I'm doing sport or not. I plait my hair for sport.
- Baseball caps: I never had one as a child, although lots of boys my age did.
- Sandals; for some reason, I never wore them beyond the age of four, even in summer. I'll wear jelly sandals out and about if I'm feeling brave. (Not Crocs: lots of adults wear them.) I never wore flip flops as a child at all, not even on the beach. I don't wear them much now, because I find them hard to walk in; perhaps I didn't have the childhood training.
- Designer sneakers; I didn't have any until I was a teenager, and had to pay for them myself. I wear them without socks, because it feels like a childish thing to do. I like Velcro or laceless sneakers, because they feel more childish.
- Black canvas laceless plimsolls, again without socks: I must have been the only child my age who never wore them.
The clothes I wear at home to indulge my little side (not out and about) are:
- Big fluffy animal slippers, and I'm very tempted to wear the big fluffy sliders that some women wear outdoors. Any slippers I did have as a child were old-fashioned tartan ones, that 1950s kids wore.
- Gingham school summer dress, and T-bar shoes without socks; but if I had been a girl and had to wear this, I probably would not wear it now.
- Ribbons in my hair.
- Onesies.
. I look for kids clothes that are xl 
