In a sales encounter, it would be appreciated if the customers did none of the following:
1. Express interest when there is none.
2. Make disparaging remarks to the salesperson about the product
3. Lead them on for a close and drop the ball in the last minute
4. Profess in honouring commitments with no intent on doing so.
5. Try to hijack the presentation when they know nothing about it.
In short, don't waste my fucking time.
1. It takes time away from customers who want to be helped
2. It wastes my time
3. It wastes your time
People need to say they are not interested if they don't care or not interested. Don't talk to me, don't pretend to care and don't waste me time. Just say it; I will feel better and move on.