I became a linguist sort of by accident.
(When I was little, I
wanted to become a bakery owner, a singer, an actress, a writer,
and/or a Supreme Court judge.) But this accidental
path has taken me to a place that I'd call a utopia.
People like me do linguistics largely because it's fun. But
another reason is that only humans have
linguistic ability that is unbounded in scope and it is believed to be pre-wired in our brains.
So by studying principles of language, we can have a better understanding of the human mind and ultimately what
makes us who we are.
(Note: many linguists are good at baking, singing
and even acting, not to mention writing and arguing/judging.)