That's something I've wondered about lots too. On one hand, you want to provide as "appropriate" accompaniment as possible, but if all the songs in a set have a similar feel then it's boring to me as both a listener and a player. How much do you mix it up so the songs aren't same-y?
I see people totally loving bands whose repertoire is full of similar-sounding songs and I know I'm missing something. It's the same reason why I often struggle to understand where Rolling Stone magazine is coming from.
As you said, it's the emotional side. Being ADHD, I struggle to keep focused on lyrics long enough to understand them. So I hook more in to the form of the music than the content. I seem attracted more to the design of music, especially the "colours", more than the meaning. Superficial as hell - I just like cool sounds
Result is, I have generally varied the colours of my various bands' songs more than most other rock-based drummers. Some would consider my approach to some songs as sub-optimal, and they would be right if you refer to "optimal" as something that most listeners - both educated and uneducated - think is better.
But the way I see it, good jazz drummers often provide a broad palate of colours within each song. If I don't had the chops I'd do that too, bust since I don't I provide a broad range of colours over the course of a set.
So our playing is heavily slanted by our personalities, which of course determines our tastes. It also depends on how much influence other peoples' tastes have on your playing - broader audiences, local audiences, the band and your friends. I have almost always played to please myself and band mates in about equal measure, without much thought about audiences.
That's my 2c, which of course is about how much money I've made from music