In Crooks’ opinion, why does George travel with Lennie?

In chapter four of Steinbeck's novella Of Mice and Men, Crooks pours his heart out to Lennie about his loneliness. Like Curley's wife in the next chapter, Crooks seems to feel comfortable telling Lennie the most intimate details of his life. He senses that Lennie, who is mentally challenged, is a safe person to share secrets with because, he says, "A guy can talk to you and be sure you won't go blabbin'." He suggests that this is why George travels with Lennie. Crooks believes it is important for two people to be together, sharing the same experiences and, most of all, having another person to talk to. It doesn't really matter if Lennie understands what is being said (he usually doesn't). Rather it is the experience of two men talking that is important. Crooks says,

"I seen it over and over—a guy talkin' to another guy and it don't make no difference if he don't hear or understand. The thing is, they're talkin', or they're settin' still not talkin'. It don't make no difference, no difference...George can tell you screwy things and it don't matter. It's just the talking. It's just bein' with another guy. That's all."

Indeed, the idea of simple companionship is one of the important themes in the book. George travels with Lennie because it is far better than traveling alone and having no one to talk to. Crooks and Curley's wife are two of the characters in the novella who do not have that companionship but yearn for it, and that is why Lennie is a sounding board for their hopes and fears. Similarly, George carries on and on about his dream farm to Lennie, who doesn't understand much of it other than the idea of tending rabbits.