Why be a centrist?

PREMISE:
"The test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function. One should, for example, be able to see that things are hopeless and yet be determined to make them otherwise."
-F. Scott Fitzgerald

CONCLUSION:
It is easier to be a dogmatic, true believing leftist or rightist, than it is to be balanced thinker/activist---a centrist. Being a centrist requires more mental work, and greater abilities of judgement and innovation than to be leftist or rightist. Being a leftist or rightist, a conservative or liberal, has been and will always be the easier road to follow.