At the end of the Macy’s Thanksgiving Day Parade, Santa Claus makes his way to Manhattan’s Herald Square on his float. This moment is as good as any to make the unofficial start of the Christmas season. And that means Christmas music is everywhere. But what if that’s a bad thing?

The first time you’re hit by the wave of Christmas music each winter, it’s probably a welcome change of pace. For most, the first few times one hears “Deck the Hall,” “Jingle Bell Rock” or “Let It Snow,” great! — memories of the holiday are generally positive and hearing these classic songs sparks these warm reminders. It truly can be the most wonderful time of the year.

The “mere exposure effect”

But exposure to the same songs for weeks on end has a downside — after a while, it gets annoying. That’s due to something called the “mere exposure effect,” according to Dr. Victoria Williamson, now a professor of music at the University of Sheffield.

In 2015, she explained to NBC News that “there’s a U-shaped relationship between the [number] of times we hear music that we like and our subsequent reaction to it” — it takes a bit for us to get used to warm up to a new song, but after a while, we begin to dislike it again.

For Christmas music, we skip the beginning of this U-shaped curve — we are already familiar with most of the season’s music, after all. So we just jump right into the enjoyment phase. And in a retail environment, that can get us to shop more.

Linda Blair, a clinical psychologist, told the BBC that “music has the most powerful impact on shoppers on all our senses. When the songs are targeted properly — when a shop gives its customers what they expect to hear — it really does get people to buy stuff. So, if you play classical music in a wine shop, sales go up. Or if you play romantic music in a florists, sales go up.”

The same likely holds true for Christmas music and sales of just about everything. And because the music ends when the shopper exits the store, he or she never experiences the bad part of that U-curve. If you hear the songs aftward? No big deal — you just turn off the radio or yell at Alexa to stop.

Torturing employees

But that’s for shoppers. For those who work in retail, there’s no mute button — and that’s a problem. As Blair explained, when you can’t turn off the music, your brain takes steps to tune it out. Says Blair, via NPR, if you’re a retail employee “you simply are spending all your energy trying not to hear what you’re hearing.” And you, therefore, aren’t focused on doing a good job.

For the rest of us, the incessant Christmas music may not be all that great either. Blair per CBS, “says listening to Christmas music too early into the holiday season may affect mental health by triggering feelings of stress. Hearing a Christmas song can spark thoughts of all the things you have to do before the holiday, like shopping, party planning and traveling.”

As the holiday approaches, the music is a double-whammy — the anxiety about time running out increases, and the utility one gets from hearing “White Christmas” for the 834th time that December is close to zero if not negative.

So like all good things, when it comes to the songs of the season, moderation may be in order.

On sale now: Dan Lewis’s brand-new collection of fascinating facts spanning history and sports to science and pop culture that will have you proudly stating, “Now I know!”

Watch this

Vanna White hosts 'Wheel of Fortune' for the first time in 37 years