I'd love to have an episode where we saw how Spike grew up. As close as he and Twilight Sparkle are, I feel like he might've been raised by Twilight's parents, especially what with Celestia still busy being the sole leader of Equestria.
He's extremely well-known up north, and folks in Canterlot and Ponyville seem to know him well too, but I imagine that first impressions of him were rather interesting. After all, while dragons now are starting to become familiar to Equestrians (certainly thanks to Twilight and Spike installing a pony-friendly leader once a power vacuum presented itself

), back then I think they were mostly just seen as migratory monsters. With how adventurous Twilight Velvet proved to be in last week's episode, maybe she thought it a lark to adopt a baby dragon!