Same music used in 15x18 as in 7x13
I've been rewatching the show recently because I got that itch a while back and despite season 7 being weaker than 1-5 and a couple of the later seasons, I'm still really enjoying binging the show again.
However, I noticed that they use the same music in one scene during 7x13 "The Slice Girls" as well as during Castiel's confession in 15x18. The whole track during 15x18 doesn't feature in 7x13, but part of it does and the scene I'm referring to is when Dean is starting to get creeped out by Lydia due to her toddler speaking fluent English so he calls Sam, who berates him for staying outside of her house.
I know its an odd thing to notice but I've watched that confession scene so many times and it's burned into my brain at this point so I picked up on the same music cue right away when I got to this season 7 episode.