This weekend, I shared with a friend what I learned about psychology from rereading The Warren Buffett Way by Robert Hagstrom. One of the things he found interesting was the concept of impetuosity and how it negatively impacts investors.

Impetuosity is the tendency to act quickly, without thinking about the consequences. It can be considered a casino mentality—an itch to go into action. You get caught up in what other people are doing and place a bet or make an investment without taking time to think it through.

Impetuosity can result in investors making bets when the probabilities are against them, upsides are low, and downside risks are high.

This section of the book reminded me of 2020 and 2021. ZIRP made investors comfortable paying high valuations for a growth company. Early-stage venture capital deals were getting done in a few days with limited diligence. In 2022 and 2023, companies that raised at these high valuations and didn’t grow into them struggled to raise capital. Some raised down rounds with brutal terms. Some didn’t make it.

Looking back, it was a period of impetuosity. Investors were doing deals they otherwise wouldn’t have because of what other investors were doing. Founders were raising at sky-high valuations because other founders were. Many didn’t think about the long-term consequences. They were caught up in the hype, doing what seemed normal.

Some founders and investors were aware of impetuosity and recognized what was happening. They took note and acted differently. The shrewd investors were selling assets at peak prices, not buying. And the shrewd founders were raising reasonable sums at valuations that wouldn’t hinder future fundraising, or they were selling their companies outright at peak multiples.

Hagstrom details how Warren Buffett and Charlie Munger avoided impetuosity. The most important thing they did before making an investment was calculate the probability that it would be favorable for them. If it wasn’t favorable, they continually took in more information and monitored the situation. They had the patience to wait until the odds were in their favor, which reduced their risk of losing money. And if the odds tilted in their favor, their research and calculated probability gave them the confidence to bet big even when others were doing the opposite.

Their use of facts and probabilities helped them act counter to the crowd and overcome impetuosity.