It's irritating because I adore coffee in the afternoon. It's even better than morning coffee for me somehow, experientially. But I also adore sleep, so it's not a worthwhile tradeoff.
And it's not that drinking coffee too late leads to falling asleep too late. It actually somehow prevents me sleeping at all, which I find kind of baffling. Shouldn't it just be that I can't sleep until it's out of my system? But it appears that if I get into bed at a time when the caffeine is still actively preventing sleep, then I basically won't sleep at all, or maybe a restless couple of hours between 5-7.
Bodies are stupid.
I may just switch to decaf all the time, and then I can go back to drinking it in the afternoon! :D