doing something
subjectively meaningless, i.e. something that is objectively useful to everyone, including yourself, except the person who uses this phrase on you, who defines your activity as
useless and
subjective only to themselves).
mother: Adam, go help your
father in the yard, if I may interrupt you. All you've been doing to day in playing
Minecraft.
Adam: okay, I'll go help dad, but remember that the purpose, of playing
Minecraft, I mean the actual game, is subjectively meaningless to youm, since everybody objectively defines it as useful except for you. (Adam goes off to help his dad).