Which are the pleasant hangover symptoms?

I said it eliminates the most unpleasant ones, leaving the less unpleasant or neutral ones. I did meet a woman once who never got hangovers but instead a mild euphoric high, almost certainly some unusual GABA related brain chemistry.

For the rest of us though, what’s left over is a mild lethargic unfocused feeling, no headaches or nausea just a strong need not to be bothered and lay around all morning.

Moderate lethargy, satisfaction from eating fatty and protein rich foods, things like that.

If it wasn't pleasant, not that many people would endure it regularly as there are.

…people are generally drinking for the immediate effects, not the hangover.

Sure, and generally you don't drink enough to get a hangover so I fail to see the relevance.