It often happens, however, that thinking lags behind reality; this is because man's cognition is limited by numerous social conditions. We are opposed to die-herds in the revolutionary ranks whose thinking fails to advance with changing objective circumstances and has manifested itself historically as Right opportunism. These people fail to see that the struggle of opposites has already pushed the objective process forward while their knowledge has stopped at the old stage. This is characteristic of the thinking of all die-herds. Their thinking is divorced from social practice, and they cannot march ahead to guide the chariot of society; they simply trail behind, grumbling that it goes too fast and trying to drag it back or turn it in the opposite direction.

We are also opposed to "Left" phrase-mongering. The thinking of "Leftists" outstrips a given stage of development of the objective process; some regard their fantasies as truth, while others strain to realize in the present an ideal which can only be realized in the future. They alienate themselves from the current practice of the majority of the people and from the realities of the day, and show themselves adventurist in their actions.

-Mao

You need to be able to see the whole situation and understand what current conditions require to advance to your ultimate ideal. If you’re not willing to make concessions for a future victory you are as lost as someone with no ideals.