Credibility is easily lost and hard to gain. If you get caught in one lie, everything else is called into question. If you were going through a company audit and the auditors found a bogus check, everything from that point on is questioned, scrutinized, and analyzed.
And in regards to Winston, lying about a crime isn't a white lie or a slanted story. A white lie is telling your wife she looks good in that dress to avoid an argument. Publix either told him he was on the Free Crab plan in which case it's an NCAA violation or Publix didn't know about it and he was stealing, or he had an accomplice who worked at Publix and they both are guilty of theft.