I used to work with a bloke whose son would go out on the town of a weekend, and inevitably get involved in a fight, every single week.
The thing is, it was never his fault - it was always the other bloke that started it; Some troublemaker that looked at him incorrectly, spilled his pint, chatted up his girlfriend, pushed in at the bar, blah blah blah.
My colleague would be telling me this with a straight face, bemoaning the bad luck his son had to always be the one that bumped into the troublemakers, and I'd be sitting there thinking 'Do you honestly believe this sh1te? Can you not see you've raised a thug?'.
Talk about being in denial. Some people are just violent and nasty.