Tiki Barber — He ended his NFL career and began his retirement horribly. First, he publicly dissed his former quarterback, Eli Manning, for lacking leadership skills and other intangibles to succeed, but then Manning went onto win a Super Bowl that same year. Barber lost a lot of respect in the NFL after hating on his former QB.
And then, Barber was excoriated nationwide when the paparazzi found out that he was cheating on his wife who was pregnant with twins in favor of a 23-year-old intern. Barber left his wife soon thereafter. These instances ruined his clean-cut image and destroyed his post-NFL career as a TV football analyst.