When you look at your hand in the thumbs up
gesture side on, if you look closely at the four curled fingers that go into the palm and notice the edge of the knuckles it looks very much like the classic early Hand Grenade
known as the pineapple hand grenade
. Now looking back at your hand in the thumbs up gesture if you curl over your thumb and imagine its inside the ring that’s joined onto the pin, then move your thumb up as if to remove the pin thumbs up
BOOM. A hand gesture thrown by the hand grenade
Friendship goes with a bang!