This is the WORST thing that a fellow passenger can do to you on a flight, I
usually try the ask nicely approach (last time I did this I was abused for not
understanding how difficult it was to travel with kids) and then resort to glares.
I keep telling myself that next time I'll ask the FA to move me. I wonder how many air rage incidents are caused by this - I know I get almost to screaming point after a prolonged attack.