Private Jackson was cocky.
Didn't anyone else think he was a tad arrogant and up himself? Just like in the field scene when he said he'd be able to get close enough to Hitler to kill him and end the war by himself. He just acted like he was the best and better than the rest of the squad. He didn't talk much to anyone else, either. I think he was a bit into himself...
Save the trees. Wipe your ass with owls!