Warning: spoilers ahead for the Game of Thrones finale!
After a very controversial season, Game of Thrones wraps up in its finale, and we can all say our watch is ended. If that expression sounds familiar, it's because it's something the Night's Watch says when one of their members dies. Remember those guys? Jon Snow reveals his interest in joining in the very first episode of the series, explaining that even a bastard like him can make a mark there while defending the North from threats beyond the Wall. And in the series finale, he . . . ends up right back where he started? He actually asks something many fans are probably thinking: "There's still a Night's Watch?"
Heading back to the Night's Watch is Jon's punishment for stabbing Daenerys, who was determined to "liberate" the rest of the known world. Naturally, since she believed torching King's Landing was a good idea, Tyrion is concerned that she'll do the same elsewhere and urges Jon to do something about it. Her death leaves a melted Iron Throne, thanks to a distraught Drogon, and Bran becomes the new King of the Six Kingdoms (Sansa is keeping the North for herself), after a vote from Westeros's lords and ladies. Though the Unsullied want Jon dead for killing their queen, Bran sends him back to the Night's Watch. Jon looks as confused as we all must have in the moment. Isn't the whole point of the Night's Watch to guard the Wall and ensure threats beyond it are taken care of? The Wall has been breached, and previous major threats — the Wildings/Free Folk and the White Walkers — are allies and dead, respectively. What exactly is Jon supposed to do without those threats around?
Tyrion tells Jon, "The world will always need a home for bastards and broken men." Part of the reason Jon decides to don black the first time is due to a sense of not belonging. At the time, he thinks he's the bastard son of Ned Stark, which makes him feel ostracized from his family and home. At Castle Black, he gains another family (like his closest friend, Sam) and rises in the ranks. There are probably other people in Westeros who have a similar experience as Jon and might want to join the Night's Watch for the same reasons. Joining also absolves members of any past crimes, and surely crime doesn't stop in Westeros just because there's a new king in charge.
At the end of the episode, we see Jon meeting up with Tormund and the Free Folk (and Ghost!) and heading beyond the Wall. It's possible that they're keeping an eye out for new threats that they and the new Night's Watch can protect the Seven Kingdoms from. Or perhaps there really is no formal Night's Watch anymore and Jon and his crew are starting anew far north? Either way, it seems like Jon is content with his fate. After all, as he mentions several times throughout the season, he didn't want the throne anyway.