I feel Ennis's anger because he wasn't ready for the summer to end when it did. He carries alot of anger in him anyway. I also agree with the whole"foolin' leads to cryin" thing, too. I think he was confused about going back home. He went right back into shut down Ennis. He was loving, laighing and sharing intimacy over the summer with Jack, and then now what? Who is he now and what did he do? The mountains (Jack) changed him and he didn't expect the feelings to be so strong.