Alex and Bob are two people. There relationship is extremely complicated.
Alice and Bob were childhood friends they were often seen playing with each other and even playing practical jokes on one and other. They were the best of friends.
One day Alice began to mature and started growing affectionate to Bob. Bob was also very affectionate to Alice, but neither one of them would confess to their true feelings.
One day Bob found Alice seeing another man, he was justifiably upset, however in his anger he chucked a water balloon at the couple. Alice retaliated with grafitti tagging Bob's house and they have been fighting ever since.
Despite their grudges Bob often invited Alice over for thanksgiving dinner, since she had no other place to go. Even if their relationship is rocky, they treat each other no differently than brother and sister.