Sometimes I had to ride the train to Tokyo for work. One morning I was sitting down enduring the boredom when an interesting man got on the train and quietly took a seat.
He was wearing ordinary clothes and not doing anything unusual, but there was something about his demeanor and the way he carried himself that made me think that he was a strong martial arts sensei.
The ride was uneventful, but several stops down some more men got on the train and joined him. One was carrying a bag that looked like it contained martial arts weapons, and handed it to him. He put the bag on the overhead rack, and the other men were very deferential to him. They all got off the train several stops later.
If you have it, it shows. I don't know who this man was, but just got the feeling that anyone who was stupid enough to mess with him would be in for a very unpleasant surprise.