Curious about the can

I have three questions about the bathroom and related activities:

1. Why do some men wash their hands before doing their business in the restroom? Or am I the weird one for even asking this question? I've done it a couple of times, but only if I've just eaten and I know there's something on my hands that would get smudges on my clothes. So is this also the case each time I see someone wash his hands first? I'd really like to ask a total stranger why he does this -- not someone I know, because I'd have to talk to him again afterwards -- but I've never felt comfortable sticking around until the guy comes out of the stall. And having a conversation with a total stranger who's in a bathroom stall is something I don't do while sober. Actually, there's a better reason to stick around until he's done -- to see whether he washes his hands after as well.
   
   
2. Do you leave the toilet seat up or down? When you replace the toilet paper roll, do you have it roll forward (pull over the top and down the front) or backward? I know what I do (down; forward) but I'm not qualified to tell you that you're wrong if you do it differently. I wonder, though, whether there's a correlation between the two. Are people that leave the toilet seat up more likely to have the toilet paper roll face forward than those that leave the toilet seat down? And so on. This is the kind of research I'd do if there were 87 hours in the day.
   
   
3. What goes through a dog's mind when his owner cleans up after him with a plastic bag while taking a walk? I can imagine just about anything:

• "My owner is one sick ____."
• "Hey, leave that! I was marking my territory! Kind of like what you do with your dirty clothes."
• "As long as you're going to pick up after me, would you mind cleaning my _______ with your tongue, too?"
  
• "If I had known this stuff was so desirable, I wouldn't have eaten it all these years."