At its core, "Criminal Minds" is a show about a bunch of criminal profilers who work for the FBI — which may sound like not the most exciting premise. However, it quickly grew a large fanbase and continued to remain popular as time went on. In 2020, it was the third most-watched show on Netflix, proving its appeal 15 years after it first aired. A large part of the show's popularity is because of Matthew Gray Gubler's role. Dr. Spencer Reid is a rarity on television. He is introduced as a whip-smart young man who lacks social skills (especially in the romance department) and can be frustratingly aloof. 

Despite his aloofness, the rarity of Reid lies in the fact that he is often shown to be vulnerable instead of impenetrable, a trait that isn't usually seen in young male characters (via Collider). Of course, Gubler's good looks and off-screen personality have contributed to his character's popularity too. A natural-born performer, Gubler is warm, bubbly, and super enthusiastic. When asked about his long-running role, he stated, "I love entertaining people, and that's all I've ever wanted to do. The fact that I've gotten to do this for a long time is so awesome" (via Glamour).