What asiento do tu choose on a bus?

I try to find a spot in the back that's empty so I can sit por myself, until unfortunately obnoxious people have no other choice but to sit siguiente to me. If all seats are empty I just stand in the aisle like an idiot until someone offers me a seat. .3.'

Preferably somewhere near the door o near the driver. If not, I'll try to get a asiento at the back.