Some observations on Jargon

Is jargon the product of a new group’s attempt to make themselves secure as a community—ie, they develop their own shorthand language and can require others to demonstrate affinity and/or allegiance by proving they comprehend it?
I am thinking about how there are certain blogging world worlds I truly hate, which is meme.
What exactly is a meme? Sounds like a Greek cough drop, or a pretentious conceit for saying idea.
Tell me what a meme is in plain English, please and skip the pseudo smart stuff.
Are there jargon words you hate? Which ones?