I know work bad but if I don't keep busy, time crawls. Also, theoretically I would have bosses find me shittier jobs to do if I'm not engaged in the main thing I'm there to do.
I've never had a job that there was a lot of downtime except that time I worked for a landscaping company. My boss was chill and we smoked a ton of weed between jobs
Personally, I like to make an assessment of my feelings toward the favor done. If I feel put upon, I give an "mhmm" or "yup". My enthusiastic response is usually "no problem!"
"You're welcome" implies you can ask for favors anytime, day or night, and feels a bit too prostrate. I'll say it to some people, but it almost feels like an "I love you" type of response, and I reserve it for when I really mean it. I don't say the words "you're welcome" casually. I kind of say them like you would say something deeply truthful to someone
While we're at it, what's up with young people saying "bless you"? I kinda thought that one would have fallen off with people under 35