#Person1#: I don't know what Jim's got to grumble about. My work load has doubled in the past year and I still manage. He is not doing anything different from when he arrived, as far as I can see.
#Person2#: Yeah, but he's not as energetic as you are. Well, no one is. But the boss doesn't blame me when I get a bit behind. He is very understanding with me. But with Jim, he goes on and on.
#Person1#: I haven't noticed it. But you're probably right. I wonder why he does it.
#Person1# doesn't understand why Jim grumbles. #Person2# thinks he's not as energetic as #Person1# is and the boss is not understanding with him. #Person1# wonders why.