My favorite moments of this game range from small things that stood out, or huge encounters that left a lasting impression on me. My most favorites would be the Silver Shroud quest, Kids in a Fridge, the Mr gutsy random encounters (not gonna spoil it, it's just too good) and taking down the Mirelurk Queen at the Castle.
For as many people who say this game is a lot blander than past games, that's a lot of great moments imo.