Any number of Brazilians - Adriano, Robinho, Oscar, Hulk
Some players get unlucky with chronic injuries (Isaac Cuenca), some just poor professionals (Balotelli or Dembele) and some just flattered to deceive (Nery Castillo)
I am always intrigued as well by those that reinvent themselves to prolong their careers. Even someone like Banega who struggled with personal demons and professionalism somehow turned a corner or Jesus Navas who went from winger to FB (Alba did similar) or Zinchenko from central midfield to LB