Because you like Cosmo Kramer in Seinfeld
Haley Dunphy's interests include shopping, dating, and avoiding homework at all costs. See them in Modern Family.
Castiel might be an immortal angel, but the human world is still more than a little confusing. See them in Supernatural.
Both brave and foolhardy, Thomas trusts his instincts above all else. See them in The Maze Runner.
Mark Sloan is the best plastic surgeon and biggest playboy the hospital's ever seen. See them in Grey's Anatomy.
With a song always on her lips and her heart on her sleeve, Maria von Trapp is the governess every kid dreams of. See them in The Sound of Music.
Harvey Specter depends on no one and gets his fulfilment from ambition, material success, and expression of his own worth. See them in Suits.
Christine Palmer is a great surgeon and an even better friend. See them in Marvel Cinematic Universe.
Dolores Umbridge keeps her villainy hidden (albeit poorly) behind a sheen of sugary pink politeness. See them in Harry Potter Series.
Leonard Hofstadter is the normal one among his scientist friends, though in fairness that's a low bar. See them in The Big Bang Theory.
Jean-Baptiste Grenouille may have a phenomenal sense of smell, but he has a weak sense of morality. See them in Perfume: The Story of a Murderer.