Retail therapy is no myth. Psychologists have found that there's a real science behind the burst of joy we feel when we treat ourselves with a big, exciting purchase — no matter how impractical it may be.

Unfortunately, buyer's remorse also exists. Once the newness wears off, our prized purchase sometimes becomes just another thing in the pile of stuff that occupies so much of the space in our lives. We begin to compare it to other things like it that we don't have. A faster sports car. A bigger jacuzzi. The latest cell phone upgrade. And just like that our big buy loses its luster.

Some items are prone to invoke buyer's remorse. Typically these items are just downright absurd, yet we've convinced ourselves that they're an important, practical, or smart purchase anyway. Thanks to the mistakes of thousands of consumers before us, we've been able to identify a few of them for you. (See also: What Is Your Financial Kryptonite and How to Conquer It)

Read on for our list of the top seven purchases that are sure to leave you wallowing in your own tears of regret.

1. 3D TVs

The majority of 3D television owners regret their purchase. It's not that the technology isn't cool. The leading complaint is that there just isn't enough 3D content to make ownership of one of these futuristic devices worthwhile.

More than half the 50 movie titles offered in 3D in 2011 were kids' flicks, while most blockbuster movie titles opted out of the 3D format altogether. When you're coughing up between $2,000 and $12,000 for the TV plus another couple hundred bucks a pop for the glasses, that's sort of a deal breaker.

That leads us to another popular complaint: It can be a major annoyance to wear the glasses that make the third dimension pop. Sort of like wearing your sun shades in the house.

2. Whirlpool Tub

It's a vision of romance: Flower petals, candle light, a bottle of wine — and then you turn the thing on. Who wants to canoodle with that grumbling sound? Yeah, it's a vision alright.

Jacuzzi-style whirlpool tubs can be a real mood killer. Not only are they noisy, they're time consuming to fill with water and prone to completely draining the hot water tank. Plus they're expensive to operate, not to mention expensive to buy and install.

Bottom line: Most people don't use them enough to outweigh the negatives.

3. A College Education (No, Really….)

Okay, so most people would say a college degree is a smart investment — but it can certainly be regrettable. A third of millennials say they would have been better off working than going to college, according to a Wells Fargo study. The reason? They're drowning in debt.

More than half the 1,414 college grads surveyed by Wells Fargo said they afforded their education by taking out hefty student loans that have become the crux of their financial distress. Many said they think they'd have been better off with a less expensive, public education than a much more costly degree from a top-tier school.

If given $10,000, more than half of those surveyed said the first thing they would use the money for is to pay off student loans or credit card debt.

4. A Timeshare

The cost of owning a timeshare extends well beyond the mortgage. Annual maintenance fees, property taxes, and special assessments are piled on top — and they can be quite expensive.

Another major gripe among timeshare owners is that it's not always easy to schedule their allotted time at the unit. In fact, it can be downright maddening. Some timeshare contracts have so severely misstated the ease in scheduling that several states have passed laws to punish these misrepresentations.

Timeshares are also difficult to unload. Few people are interested in purchasing a timeshare in the aftermarket, meaning you're very likely to lose money even if you do find a buyer.

5. A Car They Didn't Research

Nearly a third of all motorists regret their most recent car purchase, a consumer watchdog report found. Among the top triggers of dissatisfaction: The car is faulty, it costs more to run than they anticipated, or they simply didn't do enough research.

A car is one of the most expensive purchases many of us will ever make. So before pulling the trigger on a flashy sport convertible or a clunker with the little engine that could, experts say it's important to weigh all your options and do your homework.

Here are a couple good online resources to get you started: Edmund's Guide for First-Time New Car Buyers and Popular Mechanic's How to Buy a Used Car Without Getting Burned.

6. High-End Designer Bags, Clothes, and Shoes

Speaking of cars, a Gucci handbag can cost more than the down payment on your vehicle. Ditto that for many designer scarves, furs, and dresses. What you're really paying for is an air of luxury and exclusivity.

Many of the clothes and accessories we find to be swoon-worthy at the store, high-end and otherwise, end up spending nearly their entire existence in storage. That's because the average person wears only about 20% of the clothes in their closet, according to retail specialists.

Among the top reasons our garments go unworn? The items no longer seem as unique or important as when first purchased, or we realize it was an impulse buy rather than a smart, practical purchase.

7. A $5,000 Watch

So you got a big promotion at work. Why not reward yourself with a Rolex? You earned it. Plus, what's more practical than a classic timepiece?

Ted Jenkins, who co-operates a financial advisory firm focused on generations X and Y, speaks from experience when he says: "Don't do it!"

"The dumbest purchase I ever made was spending $5,000 on a watch," Jenkins wrote on his financial literacy blog. "I wore two watches over the course of a year, one that cost $5,000 and one that cost $79. The $5,000 watch was a Panerai and the $79 was a Diesel… During that year, my compliment ratio was four to one in favor of the $79 Diesel watch. I never really cared that much about brand names and it taught me that nobody else really does as well. Now I don't even wear a watch because my phone can tell time."

Have you ever made a big dumb purchase? Please share your experience in comments!

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