Answer:
#1 Ponyboy was walking alone after the movie, and he knew he could easily get jumped by a group of Socs-when he fell asleep at the park.
#2 When he ran out of the house(after Darry slaps him), got Johnny and decided that he was going to run away.
#3 Ponyboy thinks Darry doesn't like him but he's just trying to push him so Ponyboy can be successful, but Ponyboy is to blind, oblivious, or ignorant(whichever you choose to call him-I'm not trying to mean that in a rude way, I just can't seem to think of a more polite way of putting it) to realise it.
Basically, Ponyboy is good with books, and writing but when he is in the streets with the Greasers, Ponyboy is lost, and doesn't think about the simplest and safest things. He never uses his common sense and always gets into trouble because of this. The phrase means he doesn't think before his actions; he lacks forethought.