years ago, I shared a apt. with a guy, i worked for a airline so was away most of the time, I came home one day to find the lock on the door had been changed, and my stuff out in the dumpster, he had been collecting my half of the rent, and not paying the landlord, hence I was homeless, even tho I had a full time job.
since i was on the lease my credit was trashed and no one would rent to me. 
i was homeless for almost 5mths until i was able to get back on my feet,
until you have walked that "mile in their shoe's" 
just remember, most working people today are only two paychecks away from being homeless themselves