Kinda going along with what both of you said, I agree that their relationship with each other makes for a great subplot in any kind of story. I think it's a major reason WHY I love drama and suspense so much in this fandom - it's not just about bad things happening to the Boys, but how they deal with bad things happening to each other. I love stories where they have to protect each other, take care of each other, or struggle with the fact that they can't do those things.
I am definitely in a bromance phase right now, where most of my story ideas have a focus on the relationship between two of the guys or the whole group. Not in a slashy way this time, although I wouldn't be opposed to writing another slash at some point, probably with a different pairing.
Oh, that reminds me of another question I thought of at some point this summer and never posted (at least I don't think I did... ignore me if I did and already forgot LOL). For those of you who write slash and have a favorite pairing that you always write about, how do you keep it fresh from story to story? I'm talking stand-alone stories about the same couple, not stories in a series. This is not a criticism, just a curiosity. In my very limited experience writing in this genre, I feel like I put everything I had into developing the relationship between Howie and Nick in SAMS and its prequel, so the thought of writing a completely different story with that Howie/Nick pairing doesn't appeal to me at all, anymore than taking a het couple from one of my romances and writing a completely different, unrelated story about them would. How are you able to keep it new, different, and exciting each time?