And I've also got another thought... and an obvious one as well.
We already know (from science) that our body possesses multiple happiness hormones. In order to feel ourselves truly happy, we have to "activate" them- and that means acting across different spheres! At least according to this website. So in order to feel good, we have to work out (endorphins), social communication (endorphins and dopamine), going outside (serotonin), intimate connection (oxytocin), etc. If I truly want to feel happy, then I have to activate all of these hormones.
To be honest, thats what I've noticed myself: only sitting at my table and binging YouTube means that my reserve of dopamine will get depleted very quickly, and I won't have any happiness feeling at the end. In contrast, when I go for a walk with my dog, I feel pretty good after that- but it's not the same feeling as when I binge YouTube.
That's an obvious thought, but I haven't thought of happiness hormones at all! I simply forgot that we had different hormones for different stuff, and tried only to active my dopamine reserve (which obviously failed). And that, in turn, led me to doubt Epicureanism. But the man was right in the end, although he couldn't knew of happiness hormones and stuff.