Well, I'd say whatever you do regarding friendship, it should come naturally. So don't "force" yourself to conform to the 80/20 rule. And who made that rule up anyway? Obviously, each friendship is unique. And to say nothing of the fact that the rule doesn't even make logical sense. If one gives 80% and the other only receives 20%, where did those extra 60% go? I.e., it would only be logical for each person to receive exactly as much as the other gives, so it should be 50/50 or some other pair that adds up to 100, or even more than 100 because of the effect of synergy/positive-sum "games." And one more thing, giving, whether forced or not, shouldn't amount to shoving something down someone's throat...that implies vulgarity, inconvenience, force, deleteriousness. I mean, if you'd have to "shove it down their throat," it'd probably better for them that you not give.

EDIT: Er I mean I know that 80/20 does actually add up to 100, but by the wording it seems to be saying that each person gives 80% and receives 20%. It would be more logical if, for example, one person gave 80% and received 20% and the other person gave 20% and received 80%.