Do men remember every compliment ever??

I think this stems mainly from a different level of investment between men and women. While this isn't true of the whole, men find it easier to compliment women because they're more invested, or at least that's the way it seems. Whether the intention behind the investment is innocent or naughty is up to interpretation, but nonetheless the point stands. I'd wager a decent portion of men would say that the number of times they genuinely inquire after a woman's wellbeing, activites, hobbies or struggles outnumbers the times that it comes back to them. Nonetheless, men also know that women, like anyone, like to hear compliments, so we do it. I suppose it's something that's hard to see from the inside.
Not making this comment to have a go at any particular group, but just to express the nature of experience.