Why was Chris McCandless relieved when Franz wasn't with him anymore?

I don't think we can say with any assurance that Chris McCandless was relieved to have left behind Ronald Franz. McCandless seemed to really enjoy his time with Franz, and McCandless wrote lengthy letters to him and made sure to call him on his birthday. I believe that McCandless missed Franz, and looked forward to spending more time with him. I believe that because McCandless came back to spend more time with Franz. McCandless did...

I don't think we can say with any assurance that Chris McCandless was relieved to have left behind Ronald Franz. McCandless seemed to really enjoy his time with Franz, and McCandless wrote lengthy letters to him and made sure to call him on his birthday. I believe that McCandless missed Franz, and looked forward to spending more time with him. I believe that because McCandless came back to spend more time with Franz. McCandless did that on his way back to Carthage after his stay in San Diego didn't go so well.

Upon his release he had hitchhiked to Coachella, just southeast of Palm Springs, and called Franz. As soon as he hung up the phone, Franz rushed off to pick McCandless up.

“We went to a Sizzler, where I filled him up with steak and lobster,” Franz recalls, “and then we drove back to Salton City.”

I do understand your question, though. I found it odd that McCandless would enjoy being around Franz, and it makes sense to think that McCandless might have wanted some space from Franz. From the very moment that McCandless met Franz, I thought that their relationship wouldn't work, because Franz admitted that he wanted to get McCandless to make something of himself.

After attending church that Sunday, Franz decided to talk to Alex “about how he was living. Somebody needed to convince him to get an education and a job and make something of his life.”

That's the kind of thing that initially pushed McCandless away from his own family. He didn't want anybody telling him what to do and where and when to do it. Despite Franz's desire to get McCandless to do something other than wander, McCandless spent a great deal of time with the old man. I don't think that McCandless left Franz because Franz was becoming tiresome. I think McCandless left the Anza-Borrego desert area because he got the "itch" to move on. McCandless's desire for the road always outweighed his relationships with people.