My eldest son competed in his first jujitsu tournament this past weekend.
When he decided he wanted to participate, I was excited for him, and suspected he'd do well; he's been training twice a week for the past nine months, and his coaches have said he's a good student who learns quickly. He's only nine years old, but he's stocky and strong, and I knew his natural gift for strategic thinking (as demonstrated by his excellent chess skills) would serve him well as he tried to anticipate what his opponents would attempt to do.
Unless you count watching UFC tournaments on television, I haven't studied any jujitsu in my life. So on the day of the tournament, I didn't have any technical advice to give to my son.
But before his first match, I grabbed his shoulders, looked him in the eye, and gave him some words of wisdom I knew would be helpful:
"You can beat everybody... but don't underestimate anyone."
My son had a lot of confidence in his abilities and went into the tournament believing he was going to come out of it with a gold medal.
Self-confidence is good. But overconfidence will get you every time.
I knew my son needed to believe every opponent was as skilled as he was, whether or not that was the case. Nothing but disappointment can come from underestimating an opponent.
My son decided to take my advice; he gave each of his opponents his full attention and didn't take anything for granted during any of his matches.
It turned out to be a winning strategy.
But you didn't need to be an expert in jujitsu to know that.