Startup founders need inordinate amounts of passion to succeed. Passion is the self-created drug that inspires startup founders to press on during tough times. Since the startup roller coaster goes from incredible highs to suicidal lows in a matter of moments, it’s important to leverage passion as a driving force. But when is there too much passion?

It’s absolutely possible to be too passionate. Startup founders get blinded by their passion all the time. Passion blinds us to reality.

Passion impairs our judgment. When things aren’t going well, and money is running out, startup founders have to make tough decisions about staff. Who do we fire? When do we fire them? How many employees do we fire? Passion delays tough decision-making. Compassion too.

That’s bad.

Passion compels us to launch startups and build products even if we’re not ready. Founders often say, “I’m doing it. No matter what. I’m building this thing.” Oh ya? Why? Are you sure you’re solving a super-painful problem? Have you validated anything with anyone?

Startups can’t succeed on passion alone. Startups are built in the current reality of our times (with an eye to the future.) Startups succeed with validated markets, a focus on key metrics, super strong teams, co-founders that get along, aligned investors, active customer service, etc. Startups can’t escape those realities.

When founders recognize the importance of focusing on metrics, markets, business models, user acquisition strategies, etc. — things based in reality — and they can successfully overlay an absurd level of passion on top, to drive their initiatives and intensity, they can succeed. That’s the balance. Passion driving reality. Sometimes passion pushes us past reality, and that’s fine, but we still need to find a balance.

Don’t lose your passion. But don’t let it blind you either.