“There was no prefabricated love interest that was built in the show under my direction,” says CSI creator Anthony Zuiker while chatting for the show’s 25th anniversary. Yet, we still got Gil Grissom (William Petersen) and Sara Sidle (Jorja Fox) — aptly known as GSR (also gunshot residue) — whose relationship continued onscreen into the sequel CSI: Vegas.

(Fans did notice the chemistry between Marg Helgenberger‘s Catherine and Gary Dourdan‘s Warrick, but Zuiker admits he can’t remember any origin story there.)