Why do people so eager to say "thanks"?

thanks.

Its called common cour·te·sy
ˈkərdəsē/
noun
noun: courtesy

the showing of politeness in one's attitude and behavior toward others.
"he had been treated with a degree of courtesy not far short of deference"
synonyms:   politeness, courteousness, good manners, civility, respect, respectfulness; More
chivalry, gallantry;
graciousness, consideration, thought, thoughtfulness, cordiality, urbanity, courtliness
"our customers will be treated with courtesy"
    a polite speech or action, especially one required by convention.
    plural noun: courtesies
    "the superficial courtesies of diplomatic exchanges"
    (especially of transport) supplied free of charge to people who are already paying for another service.
    modifier noun: courtesy
    "he traveled from the hotel in a courtesy car"

But its a shame i am afraid to show it for fear of ban go's against my upbring

When I use to regularly enter giveaways, I'd try to remember to thank the creator. I feel that it is a polite thing to do, and I always appreciate when other people thank me. People who get upset about it are either annoyed by the notifications, think that the comments are insincere, or are just grumpy people.

But... but my mum taught me to always say "thank you" when accepting a gift from a stranger!

P.S.: I find it more polite not to spam inboxes with generic "thank you" messages. I do thank if I win, and I do comment if I have anything interesting to say, though.

I think maybe it's because I'm British and we are nothing if not needlessly polite (football hooliganism and rioting excepted, obviously - oh and when we've been drinking, and when we're fighting unnecessary wars, and a few other times, come to think of it...)