In particular, I remember moving into Navy housing in Long Beach, CA while I had a fever. Waiting for the guys in the truck to unload my bed and curling up, shivering, on the bare mattress while my parents dug through boxes for a blanket. My dad tucking me in while I drifted off to restless sleep in a rare tender moment.
It was easier to immerse myself in books and play with my siblings than it was to make new friends. We would be moving again in a couple of years and I'd have to do it all over again, anyway. Safer to rely on more permanent things.
I didn't learn games or sports with other kids for much the same reason. I think now that I would have liked to play baseball in high school, but some of that is probably middle-age hero dreaming as I watch the pros today. I recall clearly, however, thinking when I was 8 or 9 that I'd make a good first baseman because I had the "keep one foot on the bag and lunge for the ball" thing down.
I came out of that experience pretty sure of myself (once I got out of adolescent awkwardness) and independent. I'm still kind of shy and reserved with people I don't know well but I'm much better at taking the initiative in talking to folks. (Made some new friends at the Irish festival last year that way. Just walked up and said, "You look like you're having the most fun out of the folks here, mind if I join you?" Wouldn't have done that a few short years ago.)
Oddly, I'm not very close to my brother and sister. Nor to any of my family in particular. I'm not sure if I internalized them as "just people" and, therefore, non-permanent, not to be trusted to be there, not to be relied upon or if I just took the "rely on myself" thing to an extreme.