I have no idea what Holly means in panel two. Is she on her knees a lot? Does she scrub a lot of floors, or is her Dorf impression hugely popular at parties? When one says “I’m on my feet a lot” it tends to mean “I’m very busy.” I don’t know the corresponding meaning for knees.
Panel three is the real baffler. I really have no idea what she means. It’s framed as if it’s a punchline, but I cannot find a trace of humor in it–or anything sensible. Her knees want her to die so they can rest? Is that the joke?
Proof positive (as if any more were needed) that this is never touched by an editor.