He that wrestles with us strengthens our nerves and sharpens our skill. Our antagonist is our helper.

Opposition does something for you that agreement cannot. Somebody pushing back forces you to find the actual reasons for your position, tightens the sloppy parts and shows you where the argument gives way, which is work you would never do alone. That does not make the antagonism pleasant or the person kind. It makes them useful in a way your allies are not.

Think of whoever most reliably disagrees with you and ask what they have been right about. Take one criticism from them seriously enough to test it. Then notice how much weaker your thinking gets in rooms where everyone nods.