On the pilot episode of Star Trek: Voyager, Robert Picardo's character, the Emergency Medical Hologram, was sarcastic and appeared to be disinterested in what was going on around him, which made sense considering he was a hologram. He wasn't supposed to express emotions. And to top all of that, he wasn't supposed to be Voyager's permanent doctor. Fortunately for fans, that was the case, and Picardo was a series regular on the show.
Picardo told Larry Nemecek in the July/August 1995 edition of Star Trek Communicator, the magazine of Star Trek: The Official Fan Club, that he was "gratified and flattered" even though he was playing "kind of a jerk." But that acerbic wit and droll sense of humor earned him legions of fans, and, according to Picardo, Rick Berman warned him that his character was "going to be one of the most popular characters in the show."
Picardo thought Berman was just being nice, but Berman knew exactly what he was talking about, which is why Picardo's character has made a return in Star Trek: Prodigy's second season and will be a series regular on the upcoming Starfleet Academy.
Though it might seem strange, arrogance can be a draw for fans. Just look at Hugh Laurie's House or William Shatner's Denny Crane on Boston Legal. They both thought very highly of themselves to the point of being offensive to the other characters on the shows. Still, they were popular. Shatner even took home two Emmys for his portrayal of the completely full of himself Denny Crane.
Picardo himself was nominated for a Saturn Award for his portrayal of the Emergency Medical Hologram and returning to a series full-time opens up plenty of additional opportunities that, we can only hope, will land him an Emmy.