John Stamos is opening up about coping with the loss of his best friend.The actor took to Twitter on Thursday morning to reflect on how difficult it's been since Bob Saget's untimely death on Sunday. Their 'Full House' co-star, Dave Coulier, also reflected on his and Bob's longtime friendship with a series of never-before-seen photos he shared to Instagram on Thursday. Another comedian mourning the loss of the late actor is Tiffany Haddish. When ET caught up with the 'Girls Trip' star, she emotionally shared why Bob was like a father figure to her.