A good chunk of him doesn't want to see Rocket again. Even for that brief time they spent together, he misses him, but at the same time he wants to be dead for them. Their pain would be less because he was gone, no longer exacerbating it. He doesn't want to inflict himself on 'em anymore. None of this he says out loud.

"I bet it gets irritatin'. No one really understandin' exactly all the complications you had from home. Someone from there'd get it, whether you knew 'em or not. Sometimes I get jealous of Terran folks that are all from similar worlds. Not too bad? Just a little, in that they just get it real easy when they talk to each other."

No explaining wars or cell phones or cars. It's just there.