text:  Andy Field, ABC News, Washington. This is ABC News. Matt Walsh, weekday afternoons at 2. Social media, especially TikTok, is a factory for a social contagion. Behaviors and lifestyle choices, concepts, ideas can go from fringe to trendy to mainstream quite literally overnight. What was unusual one minute might be ubiquitous the next. And people, especially young people, can get caught in the current and drown before they even notice that their shoes are wet.