What Most Founders Get Wrong When Choosing a Cofounder
Psychological fit matters more than skills. Here's what to look for.
Posted May 21, 2026 | Reviewed by Margaret Foley
Two founders, two years in, sitting across from each other in a conference room that used to feel full of expansiveness and possibility. No one is yelling. Their vacuous silence has a specific texture. It's not anger ; it's something more like resignation.
As a cofounder coach, I've sat in that room more times than I'd like to count. What strikes me every time is how avoidable it was—not the conflict itself, but the degree of surprise. These two people chose each other. They evaluated resumes, checked references, and maybe even did a trial project together. But they never asked the questions that actually matter.
Research suggests that cofounder conflict contributes to roughly 65 percent of startup failures (Wasserman, 2013). Most of those conflicts don't start with a bad business decision; they start with two people who never understood how the other one handles pressure, processes disagreement, or defines success in the first place.
First, Ask the Right Questions
The wrong question is "Can we work together?"
The right question, the one that no one asks, is: What happens to this person (and to me) when things get hard?
Founders are good at evaluating technical skills. They understand domain expertise, execution track record, and complementary roles. These are visible and easy to assess. What's harder to see is whether their first move under pressure is to find fault outside themselves, what unconscious needs they're bringing into the partnership, and whether any of that will surface before it's too late to change.
Psychoanalyst Henry Dicks (1967) proposed that close partnerships form around implicit agreements built around what each person needs and fears. That's true both in the marriages Dicks analyzed and in the business partnerships I've supported. I've watched it play out in boardrooms, co-working spaces, and late-night Slack threads. Two founders feel that early sense that you're on the same frequency, reframe it as shared vision or good chemistry, and never examine what's actually pulling them together. Sometimes these unconscious agreements hold. Often, they don't—their expectations need to be made explicit and modified over time as the business evolves.
Five Patterns Worth Examining Before You Commit
Rather than a vetting checklist, think of the following as areas of genuine mutual inquiry. Both people should answer and ask each other follow-up questions.
Ask each other: What are your most significant challenges when working under pressure? What's the most honest thing you know about how you function emotionally under stress ?
The quality of the answer matters more than the content. Someone who can't identify their own patterns—who presents as having no real challenges—is either not self-aware or not being honest. Both are problems in a partnership that will ask you to hold each other accountable for years. The bar is whether they can name what makes them hard to work with and respond non-defensively when someone else names it first.
2. Stress architecture
When you're overwhelmed, how do you decide what gets your attention first? What support systems do you rely on during hard stretches?
The loneliness of early-stage building is real, and most founders aren't prepared for it. Founders who depend entirely on their cofounder for emotional regulation can create an unhealthy dependency. You're looking for someone with a support system complete with mentors, friends, and their own grounding practices that doesn't put all the weight on you.
After a disagreement, do you move on quickly or need time to process? Tell me about a time you received difficult feedback and didn't like it.
Different recovery styles don't signal underlying incompatibility. The problem is when no one names the mismatch and both people spend months assuming the other is being difficult. Pinpointing how you process emotional information can help you identify relational dynamics faster and with greater efficiency.
4. Motivation and values
What drives your need to achieve? Do you care more about financial return, impact, control over your day, or something else?
Vague answers like, "I want to build something meaningful," or "I care about impact," tell you almost nothing without elaboration. The more useful question is whether they're running toward a vision or away from something unresolved. That distinction shows up most clearly when the company hits a wall: in how they handle failure, what they give up when the company asks more than they expected, and whether they can separate their ego from the outcome.
Ask about values explicitly. Where you diverge isn't inherently problematic, but if you diverge and can't have a respectful conversation about it, that's a negative signal.
5. Communication style
Do you think out loud or process internally before sharing conclusions? Do you prefer collaborating across domains or focusing on your own lane?
Neither style is a problem on its own. The problem is when no one names the mismatch and both people spend months assuming the other is being difficult.
The Real Signal Across All Five
Across every area, the underlying question is the same: Does this person understand themselves well enough to be a reliable partner?
Notice where they locate the problem. Someone who consistently puts it outside themselves will do the same thing when the problem is you. Watch for emotional regulation—not whether they're calm, but whether they can stay present and responsive during a hard conversation rather than shutting down or escalating.
And pay attention to what happens in the conversation itself. If you can't navigate a difference of opinion during these questions, that's real information about how you'll navigate one at 11 p.m. before a board meeting.
A few things worth doing before making a commitment:
A final question to sit with: Picture this person six months from now, exhausted, convinced they're right, not interested in hearing otherwise. Do you still want to be building with them? If you're hedging, pay attention.
Wasserman, N. (2013). The founder's dilemmas: Anticipating and avoiding the pitfalls that can sink a startup . Princeton University Press.
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Matthew Jones, Psy.D., is a Licensed Psychologist and international coach who helps startup cofounding teams and executives improve communication, teamwork, and decision-making.
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This article is part of the Bringwise Psychology Journal — daily insights on human behavior, mental health, and personal growth.