I think if I ever revisit it I'll handwave all the tension as past life bleed and run with it, but it got pretty thick. Especially when Sam left for Stanford and Cas got all, well I would never leave, Dean! and it was just the two of them for four years. That's about the point where I took a step back and went waaaaiiit a second. I can write Dean and Sam gen just fine but Dean and Cas have to be all profound bond all the time.