Looking to get to a specific location using Muni from Union Square? Check out these videos (all trips start at the corner of Stockton Street and Geary Street):
Golden Gate Bridge (~ 35 minutes)
Pier 39, Fisherman's Wharf (~ 27 minutes)
Ghirardelli Square and Aquatic Park (~ 24 minutes)
Lombard Street (~18 minutes)
Alcatraz (~ 20 minutes)
Moscone Center (~ 8 minutes)