Shannymara - thanks for the useful poop page!
One thing though: Hemhorroids are not veins, they're pads, that inflate with blood to protect the anus while a poop is coming out, they normally deflate afterward and no problem. Sometimes they develop trouble springing back, and you get hemhorroids. There's a web site called "embarrassing problems" or something that, that talks about stuff like that, it's a useful site also. If you're American, chances are you have hemhorroids, whether you admit it or not. Remedies are cleanliness, salves, regular habits, and a well-trained, well-executed, regular poop habit. That first cuppa coffee in the morning, or even a large glass of water first thing, will get things moving. I know this because I have the things!

I think I got 'em because of less than optimum access to toilet so a lot of holding in of poop, more people than toilets you know, not enough to eat which anyone will tell you will constipate you, then getting into electronics which had me sitting more than I'd ever done in my life, and finally some weight gain and alcohol use, which sure don't help (I'm slowly losing weight and no longer drink).
There are all kinds of nifty medical sites aimed at doctors that will explain the mechanics of the asshole and various ways to overhaul it, but I find it significant that the sites recommend management before surgery. I also find it significant that an OLD friend of my sister's said he had 'em, and got rid of them by not sitting so much, and losing weight. So they don't have to get worse with age.
Other than electrolyte loss, which regularly kills off a few athletes and other "must make weight" types yearly, there's nothing wrong with a good clean-out if it makes you feel good. Cats eat grass, people go on juice fasts, why not? But no, there's no layer of decades-old poop inside of people, ok?