Sidestep a Muni ticket
Unlike the SFPD, Muni cops aren’t allowed to follow you, detain you, or compel you to give them your ID. No ID; no ticket. One big caveat is that if there is a police office on site at a random fare check, they can make you show ID.
Get your dollar bills in the fare slot on the first try
First, you don't have to put each bill in separately. They can all go in at the same time! Second, if your bill is really worn, fold it in half the long way to make it easier for the fare box to catch it.
Your pet can ride Muni even if he's not a service animal
Yup, Fido can ride the bus with you, but not during peak hours (Monday-Friday, 5-9am and 3-7pm). He's also got to be leashed and muzzled and he needs to pay a fare equal to your own.
You can bring your bike on the bus
But only if it's a folding bike. Regular bikes go on the front rack, which can hold three bikes at a time. If the rack is full, you've got to wait for the next bus. And you're not allowed to lock your bike to the rack, so keep an eye on it because bikes get stolen off of buses all of the time. Be sure to let the driver know when you're getting off that you need to grab your bike.
You can get off of the bus between stops
After 6:30pm, you can ask the driver to let you off between scheduled stops. Tell him/her where'd you'd like to exit and remind him/her again when you pull the cord.