What are three of Walter Mitty’s secret lives?

Only three huh?  Walter Mitty imagines himself in more than three lives, but I'll pick three.  

One of the imaginary lives that Walter imagines himself in is as killer being interrogated in a court room.  The idea pops into his head after he passes a newsboy shouting out info about a current court trial.  

Another imaginary life that Walter imagines himself in is as a brave Navy pilot.  During the sequence he is piloting a "hydroplane" through a fierce storm.  

A third creation of Walter's is that he imagines himself as one of the world's preeminent surgeons, and he has been called in to save the life of some VIP.  

What all of his imaginary lives have in common is that they are nothing like his normal life, and the people that he becomes are nothing like Walter.  They are brave, strong, popular, and well liked people.  In reality, Walter is a bit of a wallflower.  He's meek and mild and people take advantage of him often.