Heathrow is awful. I do not have much information on how airport security work (I understood from an ex high level security IT at Heathrow that the camera's already know who I am if I have been before in recent years so I have no clue why I get harassed like I am there), but Heathrow, where I have to go often for outgoing flights to Scotland, Shanghai, Hongkong and the US. I get treated far better in those places than at Heathrow. Orlando and Shanghai are absolutely cuddly borderguards compared to the bullies I get at LHR.