Payroll tax withholding problems are the scary story adult founders tell younger founders to keep them up at night. Every group of operator friends I have has a collection of stories about this. Get an accountant before you hire your first W2 employee, and use a payroll service.

Just the idea of trying to operate as a director/partner at a startup without an accountant gives me the willies. It's mindboggling to think people actually wing it past the point where they're making payroll.