Good shows will have a lot of head and body shapes, but most of them don’t and it’s just the hair. IMO the reason so many of them have horns and tails and stuff is to make their silhouette more recognizable without potentially compromising the standard “pretty face” that most otaku demand.
I remember when I was a teen a news story about malls playing a high pitched sound that old people couldn’t hear in order to annoy teens into leaving was going around. Never encountered it myself though.