Endings in sports are basically inevitable. They play a large part in sports; all games, seasons, and careers must come to an end, eventually. Happy vs. sad endings are,for the most part, black and white, but there is a slight shade of grey in it for most situations. For example, if a team is having a poor year and the season is coming to a close and the team knows they will not be playoff contenders, they will usually get a higher pick in the draft for next year. It is even said that when some teams know they will not make the playoffs that year, they will purposely lose games towards the end of they season so they can get a higher draft pick. As far as careers and games go, they usually have a black and white ending. Either your career or game ends with triumph and success, or failure and defeat.
I would have to say the most significant ending in my eyes would be the retirement of my favorite baseball player ever, Ken Griffey Jr., he retired in June 2010, halfway through the season. His career ended because of old age and a few lingering injuries, so he went out in kind of a negative way, but he was still remembered as one of the greatest baseball players of all time.