It had the biggest impact. Didn't say it was a good impact, but it was right on, that's for sure.
It was realistic. Steinbeck was writing during a time when people were reeling from the depression...he saw how desperate things could get. A lesson we seem to forget these days.
I don't care for books that sugarcoat life. It can be mean and ugly...but that just makes you appreciate the good things more.