This is exactly why I always negotiate directly with the manager. Why talk with the salesperson if all they do is waste your time? Salespeople are for undecided, uncertain, and people that don't research first.

Instead, pick a weekday quiet morning and go talk directly to a sales manager. If they refer you to a salesperson, politely refuse and head for the door. They will run after you. To use this method you must know exactly what you want, have clear understanding of the price they can offer you, and be ready to sign the deal on the spot. It also immensely helps if they have the car you want on the lot and don't have to order it.