So I figured out what causes the waves of intense well-being I sometimes experience. It’s the keto diet. On the days when I manage to stay on it (which aren’t many because the diet is an expensive, fussy bastard), I feel goooooood. Not at once but starting on the second or third day.
Apparently, carbs depress me. But spending enormous sums of money and tons of time on the fussy keto diet makes me happy. So unfair.