In "The Soldier's Home," why Krebs is so lacking in energy for wooing girls or even enjoying himself?

When Harold comes home from the war, he finds that he cannot simply pick up his life where he left off. He has been changed in a very profound way by his experiences; he now feels like an outsider in the family home and in his hometown. No one wants to hear what really happened to him, and the strain of pretending to be someone he is not--or someone he used to be--saps his energy and causes him great internal conflict. Harold has come home, but home isn't home anymore because he is not the same young man who went away. In his absence, Harold's friends and the girls he once knew have grown up and moved on with their lives:

. . . the young girls had grown up. But they lived in such a complicated world of already defined alliances and shifting feuds that Krebs did not feel the energy or the courage to break into it.

Harold likes looking at the girls, who are quite pretty, and he would like to have a girl of his own, but not enough to deal with the complications of a relationship:

He would have liked to have a girl but he did not want to have to spend a long time getting her. He did not want to get into the intrigue and the politics. He did not want to have to do any courting. He did not want to tell any more lies. It wasn't worth it . . . He did not want any consequences. He did not want any consequences ever again. He wanted to live alone without consequences.

Isolation and wounding are common themes in Hemingway's work, and they are present in this story. Harold's experiences as a soldier have left him wounded emotionally and have isolated him from the mainstream of life.