For those who work in San Francisco, especially the financial district, you can find it to be quite a hassle to comfortably get onto a BART train heading out of SF on the Pittsburgh, Richmond, or Fremont line. This is especially true for those who are boarding from the Embarcardero station (final SF station) to make the trek across the bay. If you simply get onto the BART line going in the opposite direction one or two stations to Montgomery St. or Powell St., you should be able to comfortably exit to the BART train on the other side of the station to get a seat going back toward the east bay. This also mitigates the risk of not being able to board the BART train in general during the busiest commute times of the day.
This trick only works under the conditions that:
a) You are traveling to the east bay during the peak traffic times on BART (probably around 4-5PM)
b) You intend to board on the later stops in San Francisco (Montgomery or Embarcardero) and would be willing to time the trains to back track one or two stops to ensure a seat for the duration of your 30+ minute ride to wherever your final destination is (the farther you’re traveling, the more this makes sense)