George and Lennie are migrant workers in Of Mice and Men. They have moved on from their last contract to look for work because Lennie was accused of attacking a girl. Lennie is simple-minded and had just wanted to "feel that girl's dress..." He is a big man with a child's view of life and is often misunderstood which causes problems for him. Fortunately, he has George to look out for him and get him out of trouble. Lennie feels secure and understands that, " I got you to look after me, and you got me to look after you." The men really only have each other and, despite complaining about his responsibility towards Lennie, George does feel genuine affection and wants to keep his promise to take care of Lennie.
As Lennie is a big man, everything he does is like an exaggeration. He drinks from the pool "like a horse" and has no understanding of excess or consequences. Even a mouse ends up dead after Lennie accidentally kills it whilst petting it. George urges Lennie to slow down from drinking so much, taking in such large quantities of "scummy" water which will only make him sick, but Lennie only understands that it brings him relief: “You drink some, George. You take a good big drink." He never learns from previous experiences which will ultimately have tragic consequences from which neither of them can escape.