I couldn't read all of these so I hope I'm not repeating somebody.
To get your colon inspected, you strip down to your birthday suit, then put on a flimsy gown which barely comes down to below your crotch (good thing I'm not overly well hung) and crawl up onto a solid stainless steel table the approximate temperature of Little America, Antarctica.
Then get a barium enema. YOU MUST NOT FART.
Then have them shove a tube up your butt and fill up your lower GI tract with air. Pffsht. Pffsht. Pffsht. Pffsht. Just before you think you're about to float away (bottom-end up, of course), they stop. AGAIN, YOU MUST NOT FART.
Then they ask you to move in various positions while keeping your sphincter clamped to keep the air and the barium/shit mixture from getting all over yourself (and the stainless steel table, of course). Because, of course, YOU MUST NOT FART.
All this time, of course, your brain is preoccupied with exactly one idea:
IF I DON'T FART SOON, I AM GOING TO DIE.
Oh. And the tech is the opposite gender to you, and makes embarassing comments about things seen on the x-rays which have to do with your sexual parts [T.M.I. WARNING: EASILY EMBARRASSED PERSONS ADVISED SKIP TO AFTER CLOSING WARNING] (viz. the staples that were left in when you had your vasectomy show up on the x-ray, if you must know). [CLOSING WARNING]
Now, here's the fun part. You must get down off the Stainless Steel Freezer and walk to the toilet while holding your sphincter tighter than a virgin's cervix, AND NOT FARTING.
Once on the toilet, you may unload all that air, and barium/shit mixture. Wiping after this particular bowel movement is truly disgusting. And takes several minutes. And nearly a whole roll of toilet paper.
All this to discover that the cause of rectal bleeding was an Anal Fissure (brother of Amy Fissure) and not colo-rectal cancer. Which of course makes it all worthwhile (really!) as dying of cancer in one's early 30's sux (to put it mildly).
If you've read this far, you're braver than I.