A major mistake is pursuing any potential customer. Salespeople must be willing to turn down prospects who are not a good fit, and do so early in the process. Chasing the wrong business wastes time and resources that should be spent on ideal clients, leading to lost deals that should have been won.

Revenue leaders often focus on hitting bookings targets, celebrating high-growth quarters. However, this can be misleading if the new business is outside the ICP, as these customers are likely to churn, creating future revenue and retention problems.

Company-level Ideal Customer Profiles (ICPs) are standard, but top reps should define their own personal ICP. This helps them filter prospects and avoid closing deals that, despite high commissions, will inevitably lead to churn, support issues, and reputational damage down the line.

When one customer represents a huge portion of your revenue, your product roadmap is at risk of "slow drift." Your team, eager to please, starts building features the customer "might like," not what they explicitly requested or what your broader market needs, subtly derailing your product strategy.

Founders often believe their ICP is a theoretical construct for their website and pitch decks. In reality, a company's true ICP is determined by the customers the sales team is actively pursuing and successfully closing, which can reveal a critical disconnect from the intended strategy.

Many businesses believe any paying customer is good. This 'serve everyone' mindset is costly, leading to unprofitable projects and diluted messaging. Strategically defining who you *don't* serve is as important as identifying your ideal client, as it focuses resources and sharpens your value proposition, attracting the right audience.

Serving customers outside your ICP isn't just about high churn; it disproportionately increases support load, generates negative public reviews, and distracts your team from the core product vision. These hidden costs can slowly poison a small business.

The common belief that 'anybody with money is my ideal client' is a costly mistake. This mindset leads to chasing and accepting unprofitable or misaligned customers, diluting your message and wasting resources. True growth comes from narrowing your focus by explicitly defining who is not a good fit.

Early in its journey, HubSpot secured a deal with Meta that would have doubled its quarterly revenue. However, founder Brian Halligan tore up the contract because Meta was far outside their ICP. Servicing them would have derailed the product roadmap and company focus, ultimately destroying the business.