For those not familiar with this one quote, they're standing in front of a giant tree stump w/ litter all around it.
And on a related note:
RIMMER: Lister, don't you ever stop and wonder: why are we
here? What's the grand purpose?
LISTER: Why does it have to be such a big deal? Why can't it be like,
like, human beings are a planetary disease? Like the Earth's got
German measles or facial herpes, right? And that's why all of the
other planets give us such a wide berth. It's like, "Oh, don't go near
Earth! It's got human beings on it, they're contagious!"
RIMMER: So you're saying, Lister, you're an intergalactic, pus-filled
cold sore! At last, Lister, we agree on something.
-- Red Dwarf, "Waiting For God"