There is a little known unsporting trick that riders of the X68 bus use, it's called Bus Stop Guarding.
Typically people who do it, have not been waiting the longest.

Bus Stop guarding is the art of turning up to the bus stop and hanging around the actual stopping sign to ensure they are first on, in disregard for others who have been waiting longer on the bench or the wall.
If you played football as a kid, it is like 'goal hanging'. Unsporting and frowned upon.

It matters only for the X68, as the bus is an express and doesn't stop until Waterloo. If you are the first on you get your pick of the best seat, in some cases, the only seat. Guaranteeing comfort for the next 40mins, rather than having to apply a bare knuckle grip on any bits of bus you can find as it swings around cyclists on the Kennington Rd.

Most other usual sporting x68-bus-ers who get on, like the lady with the silver pearl earrings stay back (Yolande). And get on in the order they arrive, same with a lady I call 'Betsy' who is a professional older lady, and the small man who sits on the wall near the bus stop in the order he arrived, eg before or after Betsy.

Then there's WET HEAD. Very thin lady who always turns up with her long brown hair wet, in winter she wears this stupid hat with a bear thing on the front, with her wet hair sloshing underneath. She is queen of the guarding the bus stop. She'll stroll up at 2mins before the bus is due to arrive and practically hug the sign. In blatant knowledge that Betsy, small Indian Chap, Yolande and the girl with gold hoops have been waiting there for ten minutes.

The most cleverest trick with bus stop guarding is if bus comes along that you don't want. One momentarily steps away, allowing school kids to flag it down if they need it, then two steps back and they are right up close.
It's annoying because I've seen other people think that the 'guards' want the bus and delay flagging it down. the guards then step away and the bus doesn't stop.
Equally they can stand right in the way of other people trying to get on their bus. Or queue behind them thinking they are getting on.

Only once have I successfully foiled Wet Heads plan, it happened by chance. A bus came along, it wasn't the right one, she stepped to the side. I saw on the horizon the x68 and shuffled along the pavement towards the back of the waiting bus. Wet Head was too busy guarding and when she realised she had to leave her perch as the bus had pulled up behind, she was last on.
Betsy made eye contact with me that day, it was basically a high five.

Note my example today of blonde with brown jacket (a new character at the Beulah Spa, stop). 4 buses came and went before our actual X68 arrived on time. I watched her guard, then step away, then step back, she's got her technique down, because she steps back even before the bus has pulled away, but not so the driver thinks she's trying to get on.
And Yes, when the 07.44 - X68 bus did arrive, she did get on first and yep got a good spot by the window.