You look at the loathsome snail trail left behind on the paper after wiping. I know you do. You've probably never discussed it with anyone, I sure as hell haven't, but we all do it and none of us know why, because it basically sounds like the most awful thing we can do while alone and in the bathroom that doesn't involve tools and photos of relatives.
Any time you make a bold claim like "Everyone inspects their ass wipings," you leave yourself open to that negative sort of critic who must comment on an article like this and say "Nay, Felix, you loveable scamp, I poop in utter sensory deprivation where I neither hear nor see nor smell a thing. You are foolish. Also my blind Uncle Sal has never looked."
"I can't see a thing, but it smells like s**t."
Blindness aside, the fact that this question has been asked literally tens of thousands of times on Yahoo Answers indicates to me that, yes, enough people look at the paper after icing the yule log that you're likely in the minority if you don't. You're actually the weirdo, No-Looker. How's that make you feel?
What's everyone looking for in there? That's the real question. For my part, I just want to make sure my guts didn't fall out and nothing sci-fi related is occurring. If I'm free of blood, tentacles, and gold bullion, my day can proceed as planned and I'm pretty pleased with myself. And I must admit, once or twice in my life I've actually paused and thought "What the hell caused that to happen?" when something seemed askew, usually as it relates to hue. For what it's worth, I rarely ever delve too deeply into research after the initial shock of some kind of festive green or marmalade orange disaster; I just assume I probably need to eat a more balanced diet and then go watch Netflix. Rob Delaney has a comedy special on there, you should watch it. Then wipe.