Every time my TweetDeck shoots a new tweet to my desktop, I experience a little dopamine spritz that takes me away from... from... wait, what was I saying?
I'm so glad I'm not a dentist. How many times does someone say, 'Oh, Doc, it felt so good when you were drilling my teeth'? Never. But when you give someone a wonderful cookie, you put a little of yourself in, and you see someone's face light up - that's immediate approval.