It’s just like your mama told you: Be polite.

People who are polite to customer service reps on the phone are nearly 50% more likely than those who aren’t to score a deal or a discount on the product or service they’re calling about, according to data on more than one million customer service calls that mobile advertising analytics company Marchex released Wednesday. People who were polite, first and foremost, said please and thank you on the call and were not short or snippy, explains Guy Weismantel, the executive vice president of marketing at Marchex.

Customer service reps tell Moneyish that this works in real life too. About six months ago, Sarah Nelson, a customer service manager at digital marketing agency Staylisted, got a call from a client who wanted to cancel his six-month contract, which typically isn’t allowed. But the client, who she says was “extremely polite and gracious,” explained how grateful he was for their services, but that he could not longer afford them because his family home had recently been flooded. “We refunded him for the entire six months,” she says. “If someone is really nice, super understanding, I am always willing to work with them,” she says.

And Colette, a customer service rep in Seattle, recently reconnected a customer’s phone number, even though this typically isn’t permitted. The caller used her first name and said please and thank you, and had a legitimate concern that could cost his company money — he’d printed out fliers with his now-disconnected phone number of them. “He said he’d appreciate anything I could do,” she says. “When I feel appreciated, I are more willing to go far outside of the normal process, she says.

On the flip side, being rude – as roughly 20% of callers are — is a sure way to not get what you want. Nelson says that she’s told unruly clients that “should they like to speak with us, they can call back when they are ready to have a civilized conversation.” And Augie, who has worked in customer service for a online bookseller, adds that “ If you can allocate approximately 5 minutes to every customer, if you are being screamed at for 4 minutes and 30 seconds… that doesn’t leave a lot of time for creative resolutions.”

Also see: Customer service gets even worse

Of course, simply saying please and thank you — and coming to the call with a sob story — isn’t always enough to get you the deal. Here’s what else you can do.

Step into their shoes. Nearly all of us have a some time dealt with customers. Visualize what that job was like for you before you call so you can empathize with the rep, says Weismantel.

Let the rep know it’s not their fault the issue happened. Oftentimes you’re angry at the company for doing something, but that’s not the rep’s fault. Roslyn Lash, who was a customer service rep for 18 years before she became a financial coach, says that “it gave me great pleasure to help someone that said “I realize that you had nothing to do with it, but I’m just angry.”  Adds relationship and etiquette expert April Masini,”be generous by validating what they’re saying and then add what you want or need.”

Use humor to lighten the mood. Barbara, who has been working as a customer service rep for an energy company for two years now, says customers should use humor. “It really takes the tension out of a tough situation,” she says.