OK, but a fic where Sam overhears Dean and Cas constantly whispering, but they, of course, get really quiet when he walks in the room or if they think he walks by, and then it seems like they’re being very secretive and doing things in another room without Sam supposed to be knowing about it.
So Sam is, of course, super worried something is very wrong because Dean is being extremely dodgy, and then when everything all comes to light…. all the secrets and sneaking around and hiding things is actually because they were throwing him a party for his birthday which he forgot completely about. And, naturally, all their friends are there as well with a table full of presents for one Samuel Winchester.
And Sam gets a dog.