There's a scene in the movie Cast Away where Wilson, the volleyball turned best friend for four years of the lead character Chuck (Tom Hanks), was drifted far away into the middle of the ocean. The ocean was calm and the sun is at its brightest. Chuck was asleep in the raft so he didn't noticed that he's about to lose Wilson. A whale gave him a wake up call of a splash of water, so he got up, and noticed that Wilson was nowhere to be found in the raft. He calls out for his name, looking left and right, until he saw the poor ball floating in the ocean, drifted far away from the raft. Chuck dived into the water. He struggles to swim. All he could think of was to save Wilson. But he realized that he shouldn't let go of the raft, too. So he grabbed a rope from the raft in one hand, while the other he used to swim. But the weight of the raft is causing him to swim slower. He can't catch up with Wilson. It was the time when Chuck needs to decide and choose between his best friend, and the one thing that could save his life. So after all his efforts to bring back his best friend, he decided not to go on any further. Chuck chooses to save his own life. Many times he said sorry to Wilson, and then he cried.
Chuck had him for four years. Wilson was not just a ball, but someone Chuck had devised to represent a person whom he can talk to, whom he can depend on, whom he can call a friend. They were together in an escape plan, battling to surpass the great waves of the ocean. They even made it through the storms of the Pacific.
I think it's ironic, to think that after all that you've been through, it was these unexpected situations that you tend to lose someone you value the most. In situations you least expect it.