The biggest enemy to sales is the status quo. When sales trainers say that phrase, we are usually referring to prospects. The idea is that most people find it to be very difficult to let go of what they are used to doing (even if it's not working for them) and so it is frequently difficult to persuade a prospect to make a change. Hence, the biggest enemy to sales is the status quo.
 
What is interesting is that the same rule is true of anyone in sales. The biggest enemy to your sales is the status quo-your status quo