Hmm, interesting! I'm of course projecting my own experience as well, with one parent who veeeeeery much gave my sister and me the idea we needed to please other people (especially her). A lot. (Our other parent did not do it to as great an extent, but he certainly did not promulgate the idea that we didn't need to please them.)

Me: *learns how to slither out of situations, and worries some about pleasing people until I turn 30 or so (at which point I get too busy to care) but other than that doesn't really get all that good at pleasing people or at bonding*
Sister: *worries about pleasing people to an almost pathological degree and is only starting to hesitantly get over it with years of therapy*

I mean, there is definitely a case to be made that my sister and I had different early childhood experiences; I had a personality that was really unlike Fritz very conflict-adverse and also I was very good at many things my parents valued (academics, music, competitions), which meant I had less conflict with them. And also I'm certain our mom was less stressed out with one child than with two (now having lived that). But on the other hand I think a large part of what seems to have happened with the two of us is that I didn't need parental validation the same way that she did/does.