Great hammerheads, same as any other shark, not able to swim backwards. This fact sometimes leads to such close and warm touches. This is not agressive behavior, shark just don’t have enough space to turn around after grabbing a chum, so they are pushing divers gifting them with unforgettable emotions. Thay are very strong and you can truly feel it when you try to push them away. My underwater camera was killed by hammerhead’s hard push.