Lennie

Lennie, George’s friend is basically a tall, kind and simple person.
“The rabbits we’re gonna get and I, i get to ten ’em” this quotation from Lennie pretty much sums up how he’s a simple/nice person, he’s a grown man who wants to tend rabbits like a child would want to do.
Lennie: “She’s pretty.”
George: “Lennie! Listen to me, God damn it! Don’t you even look at her! I don’t care what she says or what she does, she’s a rat trap if I ever seen one.” This one conversation between lennie and george shows that lennie is simple. He has no idea that curleys wife is bad news and he was already complimenting her so he would most likely get into trouble if curleys wife flirts with him.
The purpose with lennie’s character is that it was hard for people with mental problems to go through life back in old days because back then most people wasn’t understanding and the bad people would have a problem with people with mental problems just like Curley did.