system
Given the following post, respond as if you're commenting on Reddit:
human
CMV: allegiance to a sports team is no different from an unhealthy relationship that any rational person would tell you to walk away from.

Please note that I am not quite comparing this to an ABUSIVE relationship. The crushing defeat of your own team is not comparable to being battered by a domestic partner.

But being a fan of a sports team is, from a logical, medical, psychiatric standpoint, far more destructive to one's well-being than any possible benefit gleaned from allegiance to the team.

1) None of the positives have any enduring effect. Yankees fans experience heartbreak often despite having won dozens of World Championships. Any joy felt from a previous win is eliminated as soon as the next match starts.

2) The odds are extremely likely that your team will lose. And in fact, the better they perform, the more devastating their losses can be. Losing a championship game is not unlike continually doubling down in blackjack, winning several times in a row, but losing so egregiously in the final game that you owe double what you bet.

3) Fandom almost always fosters very specific rivalries which are overflowing with negative prejudices about the individuals who cheer for these teams. It gives rise to prejudices not all that different from real-life racism. People murder each other over sports.

4) You, as a fan, have negligible control over the success or failure of the team. Cheering for your team in person or writing nice things in your local paper about your team is nothing compared to actually being a physical behemoth with killer instincts, or being an absolute strategic mastermind of a coach, or simply fostering a team atmosphere. The only action you can take to prevent the pain is to walk away.

If your fandom were a girlfriend / boyfriend, literally everyone in your life would tell you that you need to break up. NOW.

CMV.
gpt
Almost everyone enjoys feeling part of a group with a common purpose.  It can give someone's life a certain amount of meaning.   Sports are harmless strength competitions (in the sense that it's not a real war).  There is a victor and a vanquished.  It's something people enjoy the spectacle of, even if ultimately, there is little meaning to it, like, you don't lose your village and life if your side loses.

MOST people can handle the fact that it's mostly fun.  Some people take it what might be too seriously, and a relative few take it to unhealthy levels.  However, the same can be said of almost any hobby.  Someone can have an unhealthy obsession with cars, for instance.

All in all, being a fan of a sports team is mostly harmless, but can give someone a sense of unity, pride, and to some degree, meaning.