Unless it’s practice, you will not get to pick the best possible time and place to end up as an MOB. If you had that opportunity, you might prefer to go overboard during a late summer beercan race in southern California, in the protected waters of Newport Harbor.
You might arrange it so there is a jib sheet ready to grab as you fall over the side, and, if possible, keep most of your hair dry, and not lose your sunglasses. Oh, yeah, and daylight; going overboard in daylight would be a lot better than going over at night. If you could stay within passing distance of a sandwich or a beer at all times, that would be good.
For the typical MOB, the conditions are usually not so optimal, and the risk can be much higher. Ironically, 90% of MOB deaths happen in calm wind and seas (from MOB statistics review).
The video above starts with a 3:05 head start. Watch the sailor go overboard at about 3:13. It is often this quick, but not always this easy! Your shipmates can improve your odds of rescue if they Just Throw! you a dan buoy. If you are lucky enough to be quickly found, the next step, getting back on board, can be a significant challenge. This lightweight MOB was fortunate a couple of strong guys were ready, willing, and able to pull her out within seconds of going over.
If you cannot count on luck like hers, check out the great MOB recovery gear the rest of us better keep on board.