Since we're talking about school practices, how about this one:

When kids "line up" to go out of the classroom, they usually do so by order of height with the shortest kids first and the tallest kids last.

Why not change that up sometimes too? I think that either the smallest kids could have a complex about always been the first in line, or the tallest kid could have a complex about always being the last one in line.

Imo, my underlining {over-arching} belief is that we {adults} have to be sensitive to how everyday practices may negatively impact children. Also, we need to be creative about ways we can help children & youth develop and reinforce their self-esteem because they sure as heck are going to experience some challenges to their self-esteem in life.