The answer is almost never... Almost..
How being indifferent, too good, giving the cold shoulder, and being a little bit of a jerk works out well in sales.
This is a must in negotiation. When we try to close a deal at the finish line we seem desperate which is off putting. Acting like you can live without this deal can give you the upper hand in negotiation.
This is a great voice/tone when someone is starting to act like they don't need you because they have something in-place already. You can use this tone to explain a differentiator quickly and clearly then acting like you don't care if they want your tool. ie -
Prospect - We already have this something like that.
Sales Rep - Listen there is a reason why we are working with 3 of your competitors and why they switched from what your doing to my company. If you want to book a time this week to learn more I am almost booked up except for Thursday, but I don't want to waste my time if you are not interested in learning how to make your job easier.
This is so hard for reps to do when the prospect says they are going to try out a competitor. Instead of acting desperate, being pissed off, or trying to fight for it, try saying sounds good I'll check in to see if it's working down the road. Then don't respond to messages from them over the next month. I had a guy email me back 5 times asking for a discount and I never responded until he called me, I told him no on the discount, and he signed up on the spot.
Being a Jerk
This is an art. Here are two example scenarios when I act like a jerk on the phone:
Calling into a scheduled meeting and the receptionist acts like I'm just a cold calling sales rep and says my contact is busy: "He's busy? He scheduled this meeting with me yesterday and is expecting my call". Then silence. Almost always I get an apology and the receptionist puts me on hold to go talk to my contact.
When my contact won't sign because they don't do contracts: "Jake, I hope this doesn't look like a beta technology. I'm not testing this out on you. This is a proven technology with very real results. I wouldn't waste my time with you if I was unsure on your success."
Try out these methods and you will feel different than a normal sales rep. Your prospects will treat you with more respect and you will feel better about your job.