Interesting. I noticed the same and sometimes I change my emacs theme just to get a fresh perspective. Sometimes I also disable syntax highlighting when typing so I won't get distracted.
Was waiting for someone to comment this. It's a somewhat known strategy if you have to read through a bunch of boring code you don't want to work with, and find hard to focus with, to turn off the syntax highlight and somehow the brain stops glossing over/skimming the code and starts to pay more attention.
I found it led to marginal difference at best, as with most strategies. It does work well initially though, as I guess the brain stops being able to use colors it's used to for grouping stuff together and similar.
I'm adept at using both but the change adds just enough friction and visual differences to spark creativity, or a little productivity boost.
I find it much better that way.