Personally, I really loathe ageism, always have. It has been used against me and others I care about so often that it just sickens me.
I dislike it when age is brought up for any non-scientific reason. It has no place in common English usage. It is used to discriminate based on nothing that matters.
Young does not mean stupid, old does not mean out-of-touch. Teenager doesn't mean rebellious. Toddler doesn't mean tantruming. All these stereotypes are worthless and should never be used.
I stopped celebrating my birthday at age 13, as I found the whole idea of the way age is used to be offensive. I go years without knowing how old I am, it's much nicer that way.
The birthday present I have requested from everyone that knows me, is to not mention my birthday to me.
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"Efficiency is doing as much as possible, with as little as possible."
-- Raven Morris