Steinbeck's famous story is very easy to read, yet it's still very deep and raises serious existential questions. As you must have read in the synopsis, Of Mice and Men is a short story about two rather average men (weak-minded husky Lenny and a witty weakling George) who were dreaming to buy their own farm and become rulers of their own lives. As simple as that. The simplicity of this idea and the fact that people have always wanted to be their own kings - that is what makes this story a classic and why it's still read nowadays. 
 I can say that I was indeed surprised by the ending. Up to the last pages I was certain that the moral of the story will be that people continuously come as close as possible to fulfilling their dreams (and getting their freedom) and then they get frightened and involuntarily spoil it all. Then they start over again and this circle never ends. This would be depressing enough. Steinbeck's moral, however, is even more depressing. Human degradation, comparing people to mice, doing whatever it takes for your dreams... 
 Right, all this sounds quite trivial, but nonetheless Steinbeck keeps making readers ask themselves, generation after generation - what would they do, where would they stand. I'm still not sure whether George wanted to save Lenny from worse evil and eternal humiliation or maybe he just, roughly speaking, saved his own ass in a moment of fear. Whatever the case might be, I can't say it's a page-turning book, but it's definitely a good one, a must-read and a story that leaves a very bitter aftertaste in your soul.