I don't know if this is a new thing or if I've just started to notice it , but it's everywhere , particularly with young people and it's driving me nuts.
Example
"Would you like a drink ?"
"Okay". 
A recent visit with a young family member to the cinema. " Would you like some popcorn ?"
" okay".
It gives me the rage. You are not doing me a favour .The appropriate response should be ' yes please " or "no thank you".
I work with young people and I'm correcting them every time , I can't stop myself .