The Seventh Circuit explained that the record showed that Zayas was fired after she sent insubordinate emails to her supervisor after having been warned not to. The fact that Zayas was the oldest technician and that she was replaced by a younger employee alone was insufficient to establish a viable discrimination claim. Additionally, Zayas’s insubordinate emails established that she was not meeting the hospital's job expectations at time she was fired, and Zayas failed to present evidence that other employees were treated more favorably.