Income. It takes years to get started. Look into becoming an assistant to start. This is a tip I got too late into the process.
Renumeration was not liveable. I was going into debt paying for office, telephone, parking, transportation and other necessary expenses.
Changing to a virtual work environment meant that a lot of the collaboration that happened face to face was now done over the telephone, removing one factor that is very important in communication, the face to face contact.
Poor management. No work/life balance. Employees are treated like a number with no respect.
Lack of sales ability or prospecting ability