I was so sick of how demanding the Minutemen were, I did a playthrough where I didn't join any faction. Instead, I systematically set up 20 settlements in my own name. (I accounted for the others, but didn't build settlements for one reason or another. Avoided Covenant and was too late for the Airport. The other four just didn't seem like reasonable settlement sites.) Towards the end, I needed to join a faction to build the Signal Interceptor, so I finally went to Concord to save Preston's posterior. Of course, that triggered the river of Minuteman "There's a settlement that needs our help" quests. The peculiar thing is that the MM quests only come in two "flavors"

1) Sanctuary needs help. Raiders, kidnappings, Supermutants, etc.

2) Abernathy Farm is fearful that it will be overrun by feral ghouls.

That's it; just those two quest types for those two specific locations. Help Sanctuary, Help Abernathy, help Sanctuary, help Abernathy, ... endlessly. I've completed a half-dozen quest for each site, but they show no sign of stopping.

Bug, glitch, or just really poor programming?

Since I had Preston as a companion, reached max affinity and sent him back to sanctuary. He never gives me missions anymore if i go there and talk to him. Even the radio, mission come few and far between. Actually have to wander around settlements and see if a settler asks for help.

All they had to do is replace on of his useless dialogue option with (HELP OUT) so you'd say something like "What can I do to help out?" or "Any news from the Commonwealth?" to which preston would answer by giving you a single task.

But NOPE they had to go the lazy way and make the quest dialogue a GREETING sentence.HOW DUMB IS THAT.

Once all the settlement sites are accounted for, ALL of Preston's Talk choices become, "What's next?" And there is always a next to be taken care of. And as I said, "next" is always either Sanctuary or Abernathy Farms.