Also let's acknowledge this: it's perfectly fine to have throwaway "fun" quests which are (mostly) self-contained bits of storytelling that don't really connect to the outside world. The problem arises when they are the only thing that's there. in Fallout 4 and 3 quests that are like that are pretty much the only thing that's there apart from the main quest which is also like the side quests largely self-contained and seems to have no real bearing on the game world.
A good example of what I mean by that is the two weirdly similar big story events in Fallout 3 and 4
Namely the arrival a superpower into the fray, the Enclave in 3 and Brotherhood of Steel in 4.
Nothing really changes. There's now Enclave outposts/Brotherhood Patrols going around the map. Nobody actively comments on them except a throwaway line on the radio and maybe an NPC or two making an offhand comment.
I should be more specific, before you point out the BoS in 3 and the rival factions of the BoS in 4. There's nothing that really changes in the game world. There's no Brotherhood envoy to Diamond City, no Enclave raids on Megaton, Paradise Falls or Rivet City. They're just there. In the world. Just being kinda there I guess, not having any real influence on the world around them apart from offhand comments by a random NPC, a line on the radio and a series of radiant quests about killing things and bringing back things in Fallout 4.
It just adds to the world feeling lifeless, static and just a series of unconnected attractions, each of which promises wonder and excitement but which have no bearing on eachother whatsoever.
It's like Disneyland but each ride is entirely contained in its own little shell and the when you ask the staff where the Pirates of the Carribean ride is they just say:"I live in an isolated bubble, what happens beyond these walls is not my concern. Slushie?".
But the thing is I do enjoy Fallout 4. I absolutely abhor its main plot, the side quests which are all largely a variation on "go there, kill shit, bring back something" and its worldbuilding which leaves just so much to be desired, what I do love is turning off the quests and just building settlements.
Because then, the game stops being this hamfisted attempt at telling an entirely dull and predictable mystery story which feels entirely out of place with the surroundings and becomes something actually interesting.
Fallout 4 when you're just trying to build your settlements becomes a tale of trying to rebuild after a nuclear apocalypse. You start off with a small quaint suburb, and when you run out of resources you are forced to venture out, go scavenging for resources. It genuinely makes you feel like a scavenger salvaging bits from the remains of the old world in order to rebuild a new one. Scouring abandoned buildings for office fans and glass bottles and lightbulbs, fighting with raiders who have built a little fortress from the salvage, then taking whatever useful thing that's left and going back to your settlements to build more houses, more farms, more shops and thus slowly but surely build up something new from the ashes of the old.
For an example of what I'm talking about here's the tale from my latest playthrough. I went to Diamond City not because some meth-head old lady told me to, I went there because I grew tired of grabbing random bits of scrap to get the materials I needed and decided I'd be better off purchasing shipments. On the way there I got ambushed by raiders around Lexington, cleared out some settlements that were on the way and bought a spare dog from a random encounter. not because someone told me to but because they were an immediate threat and a longer-term obstacle between me and completing my dream of turning Sanctuary into a housing block estate. Then I figured out I didn't have enough money to buy all the shipments I wanted so I did a few odd jobs for people and then realized that one big shipment of stuff that I needed wasn't even available from the merchants in Diamond City so I made the perilous trek through the ruins of Boston to another town I heard of from a random guard in Diamond City, Goodneighbor. Then I carefully made my way back home to Sanctuary Hills, avoiding raider hotspots, listening to my environment and running like hell from any super mutants I saw (suiciders are no fun). All of this happened entirely organically, no quest was needed, nothing about a missing son or any of that. Merely the desire to build some more lovely lovely housing blocks on the Sanctuary Hills Council Estate And Post-Apocalyptic Society.
Then I realized that with my level of Community Leader I could've made shops of 2nd level and they too sell shipments and there was no need for that entirely self-motivated odyssey through the wastes.
What bugs me is just how easily settlements could be used to make the game actually interesting if they were a bit more in-depth and made a more central part of the plot. Because then when you've built up a small empire, you would actually feel threatened when that empire gets destabilized by the Institute or the BoS or whoever. You'd actually care because it wasn't just some random person whose life got ruined by the Institute/whoever, it'd be the settlements you've spent literal hours building and scavenging resources for.
also because the world isn't procedurally generated there's some actual points of interest and you can actually put in quest hooks unlike so many survivalcrafting games So what I'm trying to say with this meandering overly long textwall of a 12AM post/rant is, there's a good game and even narrative hidden under the actual gameplay and plot of Fallout 4. You just have to turn off the quest markers and embrace settlement building to get there. And also turn off fast travel but you already knew that Bethesda's fast travel system is kind of shit and makes you ignore vast swathes of the world in their entirety, right? (seriously do fast travel like in Morrowind. I want post-apoc busses from one settlement to another in exchange for some caps. The settlements in Fallout 4 are perfectly placed too, there's no quest location* that's too far away from a settlement or two. Have a brief canter through the game world, you might see something interesting and/or pretty.)
*excluding the one that has you go in the center of the Glowing Sea which is pretty much just a radioactive wasteland with nothing of interest for miles around. (but there's a settlement on its edge and walking through the Glowing Sea to a given goal is like 5 minutes real-time tops)