Perhaps the greatest challenge in investing is checking your emotions at the door and making cold, calculated decisions. As much as we try, though, there are a few investments out there that are going to invoke an emotional response such as excitement for a particular stock. 

So we asked three of our contributors to each highlight a stock they find exciting for one reason or another. Here's why they selected American Outdoor Brands (NASDAQ:AOBC), Axon Enterprise (NASDAQ:AAXN), and Enterprise Products Partners (NYSE:EPD).

Excited business person following upward chart

Image source: Getty Images.

On target for greater growth

Rich Duprey (American Outdoor Brands): The market has finally -- finally! -- come around to the realization that the gun market is not in freefall, but is showing as much strength as it always has. That ought to make Smith & Wesson manufacturer American Outdoor Brands a straight shooter for greater gains than it's already exhibiting.

Both American Outdoor Brands and rival Sturm, Ruger saw their stocks tumble following the November elections on the theory that a pro-gun president and Congress would gut gun-buying demand. And though it did appear as if sales were going to plunge -- FBI criminal background checks of potential gun buyers dropped by double-digit rates for several months in a row -- what the analysts missed was that demand was still running well ahead of 2015's.

Last year was a record-breaking year, as the law enforcement agency processed more than 27.5 million background checks -- almost 20% more than the year before. But so far this year, the FBI has logged 10.7 million investigations: 7% lower than last year, yet 19% more than 2015, the previous record year.

When the FBI reported that it had processed 1.94 million background checks in May, it marked the most it had ever performed for the month, even last year. After falling to a low of $17.50 a share in March, American Outdoor Brands' stock has surged 37% while Ruger's stock is up 44% from its lows.

And both stocks still appear undervalued, but American Outdoor Brands even more so. It trades at just 10 times earnings and 14 times next year's estimates, but with analysts anticipating it will be expanding earnings 15% annually for the next five years, its P/E ratio in relation to its growth rate is deeply discounted, not to mention that it trades at just eight times the free cash flow it produces, a huge, bargain-basement markdown for a business that is so strong.

Obviously, there remain risks, such as its foray into the retail market on the periphery of the shooting sports business, but with firearms accounting for nearly 90% of its revenue still, that's the target it has its sights on and is the one that will drive it higher.

The exciting world of body cameras

Travis Hoium (Axon Enterprise): There aren't a lot of business markets that are clearly gaining momentum, are dominated by one company, and are extremely profitable. But body cameras are clearly gaining traction in law enforcement, and Axon Enterprise is the clear leader, opening up a market that could be worth billions per year. You can see below that Axon is on a growth tear and has been able to stay profitable despite investing heavily in new products and growth. 

AAXN Net Income (TTM) Chart

AAXN Net Income (TTM) data by YCharts.

What has me excited about Axon is that it has the best body camera and cloud service product on the market and seems to have built a business that can lock in customers profitably for years to come. Instead of selling body cameras, it's offering a camera and unlimited data storage on Evidence.com for $79 per month per user. With 1.1 million sworn officers in the U.S. and millions more abroad, the market potential for this business is tremendous. 

Better yet, the body camera services business has had gross margins as high as 80%, meaning it's extremely profitable. And management has invested in new capabilities like wireless offloading of data and artificial intelligence to improve usage of the data that's collected. Once officers, prosecutors, and investigators get used to using the systems, they'll essentially be locked in, even if they don't have long-term contracts with Axon. 

I think the body camera business is just getting started and Axon will start to see greatly improved profitability in the next few years as adoption grows. And when financials start catching up with the product adoption rate, the stock could catch fire.

Still selling for an exciting price

Tyler Crowe (Enterprise Products Partners): I'm not gonna lie, I'm not one to get too excited about the next great growth stock or trend -- I'm probably just too stupid to understand them, if I'm honest with myself. The thing that excites me is being able to buy great companies at a decent price. That isn't easy right now, as the market continues to climb and hasn't seen a significant pullback in some time, so valuations are at a premium.

All that said, there are a few pockets of value left in the markets, and one that still looks compelling at today's price is Enterprise Products Partners. There aren't many things I can say about Enterprise that I haven't already said, but the bottom line is that this is an oil and gas transportation and logistics company designed to have a steady revenue stream that produces predictable cash flows over time that can be returned to investors. On top of that, Enterprise's management team has proven itself over the years to be great capital allocators as well as great stewards of shareholder capital. 

This isn't a company you see making splashy acquisitions or investing in projects at questionable valuations. Rather, management is careful to invest in projects that complement its existing asset base and can supplement those steady cash flows over the long haul. This is the kind of strategy that has led to 19 straight years of payout increases with few signs that it is stretching the balance sheet to make it happen.

Even though Enterprise has proven to be one of the best in this business, its shares trade at a relatively reasonable enterprise value to EBITDA of 15.5 times and a distribution yield of 6.2%. That EV/EBITDA ratio isn't screaming-buy territory like at the depths of the Great Recession or at the bottom of the recent energy crash, but it is well within the 10-year historical valuation of this stock. With so many other stocks selling for high premiums today, this is a stock I can get behind.

Rich Duprey has no position in any stocks mentioned. Travis Hoium has no position in any stocks mentioned. Tyler Crowe owns shares of Enterprise Products Partners. The Motley Fool owns shares of and recommends Axon Enterprise. The Motley Fool recommends Enterprise Products Partners. The Motley Fool has a disclosure policy.