1. No, no one dresses up here for anything
Nope, not even work. In general day-to-day life, that guy in the red flannel and jeans is probably the CEO of a promising startup.
2. There is, however, a certain dress code for going out
Also known as: "trying really hard to make it look like you're not actually trying hard".
3. Yes, you did just smell that, and you will likely smell it three more times today
SF is, shall we say, a little lax in enforcing certain laws.
4. You will see a stranger's p*nis at some point
Even though they cracked down on general public nudity, those hardcore nudists are pretty defiant, and everyone's allowed to be naked during public parades.