Whenever I have a day that is less then my expectations ( which is most of the time ) first I go back to the old In-fisherman formula that they published religiously the first few years they were a magazine ( not so much lately)
Fish + Location + Presentation = Success. There is almost always, in all three dimensions of the formula, little tweaks that maybe/probably would have caught you more fish. The catch is fishing in the moment, being mindful and having the correct tweaks occur to you at the correct time. Easier said than done, but that is how I try to approach figuring out what happened when I have an underwhelming day fishing.
Sometimes though, it is other stuff. Tuesday, conditions seemed nearly perfect for early April, got on the water by 11 AM ( long story about why I was late getting to the lake ), then I fished all day til dark thirty, caught 4 fish - 1 around 2:30 and the other 3 half an hour before it was time to go. Last fish was a solid keeper, so that improved my attitude a little.
I don't know, I remember when I was in Pee Wee league baseball and the five coaches we had ( 1 official coach and 4 very involved Dads we were required to call coach) were very concerned that we would play the game "right". That meant, on every play, we were supposed to be at a specific place. Occasionally, as a 10 year old outfielder I would forget to come in some and watch for an overthrow at second, or as a corner outfielder, run to center if there was a hit toward center, backing up the center fielder should the grounder get past him.
Anyway, you wouldn't always do it right, sometimes you'd get benched but most of the time the coach would ask (they were pretty good about not screaming at you when you did something wrong ) "What were you thinking?" I would reply, "I'm trying." Then you'd just get that look from the coach, sometimes smiling, sometimes not, and they'd say "Try harder."
So, 50 some years later I try to apply that to fishing and what that means is that I just got to try harder, try something different, look at the situation a different way, something.