CEO who interviewed over 500 candidates shares 3 red flags he spots in job interviews

Eli Rubel believes the candidate's energy is one of the most telling signals at a job interview. (Representational image)

Eli Rubel, the Colorado-based CEO of Profit Labs and SurveyGate, has interviewed over 500 candidates and hired more than 100 people across a decade of building companies. In a recent account to CNBC Make It, Rubel shared three subtle but telling red flags he watches for in interviews — signs he says often predict costly hiring mistakes.

1. Late arrival signals poor planning

Rubel says even being a minute late to an interview raises concerns. “Emergencies happen,” he noted, “but most of the time, it signals poor preparation.” In fast-paced agency environments, punctuality reflects how candidates will manage client meetings, deadlines, and team responsibilities. His advice: log in early, test tech, and treat interviews with the same respect as client calls.

2. Polished talk without substance

Candidates who sound smooth but offer no real examples are a major concern. Rubel recalls interviews where answers “sounded smart” but lacked metrics, details, or personal experience. “In the age of AI,” he said, “leaders want proof you’ve solved problems — not just that you can talk about them.” He recommends replacing buzzwords with real stories.

3. Low energy is a warning sign

Rubel believes energy is one of the most telling signals. “The interview is your best-case performance,” he said. “If you show up flat, it won’t get better on the job.” Especially in client-facing roles, enthusiasm and presence matter. His advice: channel nerves into engagement, ask thoughtful questions, and let your real personality show.

Rubel’s bottom line: interviews aren’t just about skills — they’re a preview of how candidates will show up day after day. “Help them imagine what a great choice you’d be,” he said.