leave, at the best moment

“You should leave when things are at their best” You can't hold on to time That’s why you should take the one beautiful moment as it is and don't revel on it for so long otherwise you will lose sight of it I like this saying but on the other hand, I don't quite understand it Why leave, if it ruins the beautiful moment? When you notice: “Oh, now it’s over, what a pity” Why leave this great moment, when the farewell is so incredibly sad? I think, I know the reason but I refuse it a little bit, to accept this because happiness is finite just like time that's why you should leave it, before the joy and time has gotten over