Definitely not Bethesda's strong suit and not what I go to their games for. Their NPC interaction is made up of tons of awkward TMI introductions and dialogue too quirky to take seriously most of the time. That's a valid criticism, I would not say Fallout 4 is well written. I think it has some interesting premises like the whole synth idea, but not a well executed story.
The only overall story I really thought was good in that game was Paladin Danse's quest chain.