Why is George in mice and men disapointed about his life?

When George promised Lennie's aunt that he would take care of him, he took the promise to heart. Without Lennie, George's life would have been far different. He would have been able to hold down a job, set down roots for awhile, save some money for the future. None-the-less, George made himself responsible for Lennie willingly..... when Lennie got into trouble, George tried to fix it. All in all though, you need to remember that George really loved Lennie..... so I don't think he too awfully disappointed.