I would believe it's more to do with the degree to which a person's identity is externalised. As soon as someone doesn't have the same taste in music, clothes,

I would believe it's more to do with the degree to which a person's identity is externalised. As soon as someone doesn't have the same taste in music, clothes, lifestyle - then it is an attack on them personally. I don't think it necessarily lessens with age rather shifts to other things like postcode envy.