What to do in the public loo?

As children my brother and I asked my mother a question about the proper way to address the not-so-thrilling task of utilizing public facilities. Try as she did to answer, we were still baffled. To this day I still have a few questions regarding etiquette.

We all know how to act in public but to perform this act in a public environment leaves a lot to be desired. Common sense points us in the direction of sanitation, eye contact between strangers is rarely encouraged, and personal space is generally respected - although the trough seems to be some kind of playground at times. The specific query was about sounds. I don't think I need to go into any great detail, I'll let your imagination play it's own game. Keep in mind that the acoustics in these semi-private walled depositories are much different than those we are used to in the comfort of our own homes. Is it proper to vocally excuse oneself for audible pollution (my brother considered it bragging) or is oral communication considered taboo in this task driven environment? Recently while sitting in a rather large sanitation station, I'd say an 8-10 seater, I was flanked by a couple of guys that had let their conversation follow them into my arena. Their chat was private in nature yet there I was stuck in the middle. Had I had an opinion on the subject at hand would it had been rude for me to make a comment, or should I have considered myself included in the conversation? Association by proximity? If I spot a nice pair of Doc Martin's is it rude to throw out a compliment? These are just a few of the things that pass through my mind as I fumble with the complementary ass gaskets, balance my blackberry on the toilet paper dispenser and hunker down to shoe shop.