Severus Snape and Itachi Uchiha live their life almost in the same way. I mean, they live for their end. A bitter one. But they choose to live this only chance by that way. And they never regret that (at least that was implied by the story).
People maybe always remind this quotes: we just live once, we would never know how long that gonna last. And that I felt right after the day.
What would you like to spend your day, the rest of your life? What you gonna do for your this once and only chance? How you could be happy and haven’t any regret for your choice and your end?
Maybe that why having destination in life is crucial…