The most powerful and wise Jedi master ever. Small and green, seemingly weak, but you just try and attack him. Try! I dare ya! He'll kick your ass before you can say 'Sith'
Also despite living with people speaking normally for a good 900 years before he died, he still couldn't grasp the right way to say a sentence. This would lead to some believeing he isn't as wise as he is.
Those who believe this, die they should.
Yoda: Size matters not. Look at me. Judge me by my size, do you? Hmm? Hmm. And well you should not. For my ally is the Force, and a powerful ally it is. Life creates it, makes it grow.
Its energy surrounds us and binds us. Luminous beings are we, not this crude matter. You must feel the Force around you; here, between you, me, the tree, the rock, everywhere, yes. Even between the land and the ship.