Oh the pain this brings back! At school assemblies they always played the national anthem and I always sat through it. Burning up with the embarrassment of everyone looking at me.
A few years ago, before leaving the org but after I started thinking for myself, I decided it was absolutely ridiculous to say that if you are standing anyway, stay standing, but if you are sitting don't stand. I realized all standing is doing is showing respect. So I stood when it would be played at games, etc.