Quote 1
I want so many things that they are driving me kind of crazy…Mama – look at me. (1.2.222)
Walter's desires are complex to the point of becoming a hazard to him. To dream big can be dangerous if one's dreams are not given a chance.
Quote 2
WALTER
…Just tell me where you want to go to school and you’ll go. Just tell me, what it is you want to be – and you’ll be it….Whatever you want to be – Yessir! (He holds his arms open for TRAVIS) You just name it, son…(TRAVIS leaps into them) and I hand you the world! (2.2.131)
Walter wants to encourage Travis's dreams. He's willing to give his son everything he has, just as Lena is. This dedication to his son is what makes it impossible for him to give in to Lindner at the end of the play.
Quote 3
MAMA
Yes, a fine man – just couldn’t never catch up with his dreams, that’s all. (1.1.208)
Big Walter was never able to attain his dream. He still had hopes, though, that his children would have a chance to see theirs come true. This makes it even sadder when, both Beneatha's dreams of medical school and Walter's dreams of being a business owner are jeopardized (and possibly destroyed) by Walter's foolish business dealings with the Willy Harris.