Standing around the Nexus
(Starting disclaimer: I have primarily played ARAM for quite a while now. The following may not apply outside of that context.)
So I recently came back after a hiatus of a month or two. I have noticed the expansion of what was, when I stopped playing, fairly rare: winning teams not attacking a vulnerable Nexus. I've even had people on my team saying "don't end." I'm having trouble explaining it. It's not particularly fun to just run around or spam emotes. The team on the receiving end of this maneuver is usually dead or mostly so, so they aren't doing anything interesting. The one or two kills you might get certainly don't add anything at that point. Although, if sustained, it gives the opponent an opportunity to rally, which I have seen lead to several turnaround wins. It almost feels like feeding at that point. What's going on?