What's the difference between United Airlines and Southwest Airlines? Here's an example.

Recently, United Airlines announced it was going to replace its bonus system with a new lottery bonus system, and employees revolved. But, it turns out Southwest Airlines has had a different kind of lottery rewards program in place for more than a decade--and the employees I've heard from absolutely love it.

There are several big distinctions between the lotteries at Southwest and the one that United proposed--and then paused. We'll explain them below, along with why it makes sense that one company's people responded with anger, while the other's seem to react with glee.

Mike, from social media

I started exploring this recently after I wrote about a Southwest Airlines social media team member named Mike (last name: unknown) who live-tweeted a basketball game at a passenger's request.

Quite a few Southwest Airlines employees who read that article praised their colleague--and several told me some variation of the same thing: "We need to find out who Mike is and send him 'Kick Tails!'"

Yes, absolutely. Send him Kick Tails! Also, what the heck are Kick Tails?

Southwest spokesperson Melanie Jones explained. Kick Tails is "a stand-alone dual-purpose recognition and incentive program, designed to encourage Employees to demonstrate appreciation to one another."

About $500,000 in prizes

It's been around for a decade, and was created at the behest of then-future CEO Gary Kelly. Any Southwest employee can give an unlimited number of 'Kick Tails' to any other employee, as a way to say thanks for a job well done.

Additionally--and this is such a smart touch that I can't fathom why other companies don't do something similar--frequent fliers who are members of the A List and A List Preferred programs get eight Kick Tails per year, that they can hand out to employees on their own.

Each Kick Tail turns into a chance in a monthly lottery that gives 150 employees a prize of 20,000 "SWAG Points," which can ultimately be redeemed for gifts and prizes. (It's a little tough to calculate the value of a SWAG Point, but Jones told me she recently traded in 15,000 points herself for a total of $200 in Visa Gift Cards.)

Additionally, there's a yearly lottery: 27 $5,000 prizes last year, based on Southwest having met nine of its 10 company-wide goals. Adding all of this up, it's about $500,000 a year in total.

Every single day

So, lots of chances to win, and nice but relatively modest prizes--and I heard from employee after employee that they love this program. One Southwest worker who didn't want to be named admits to handing out a dozen or more Kick Tails to other employees every single day.

A little searching, and I found passengers who love it as well. One A List Preferred passenger said he gives Kick Tails to Southwest employees who enforce boarding rules.

So, I can sort of imagine United Airlines president Scott Kirby thinking about this program and saying, hey, maybe our employees would respond in the same way. But they didn't--not at all.

And after talking with many employees at both airlines, I think there are five key reasons. If you're just curious, or you're trying to incentivize people at your company, I'd keep them in mind.

1. Southwest's program is "in addition to," not "instead of."

Major, major reason here. The Southwest Kick Tails program is in in addition to both profit-sharing ($543 million total for 2017), and a number of other contractual employee bonus programs. At United, the lottery bonus was intended to replace their current bonus program. Moreover, simple math suggested it was going to save United a lot of money.

2. It promotes appreciation.

The program is more about saying thanks than anything else. Take that "dozen-a-day" employee, he or she (anonymity requested; anonymity given) might be saying "thank you" to colleagues a couple of thousand times a year. How can that not be a good thing?

3. It's individualized.

The current United program provides a bonus to every single United employee if certain company goals are met. United The lottery bonus program was going to offer equal chances to win limited prizes. There's a real potential "free rider" problem there. With Southwest, however, the more positive, thanks-worthy things an employee does, the better the chance to win. People respond to that.

4. Passenger-centricity.

I don't know how many frequent passengers take advantage of this program, by rewarding employees for great service. But I also truly don't know why other companies in all fields don't try this. It's empowering, positive, and potentially builds goodwill. Honestly, I'm in an entirely different business, and I'm racking my brain to think of how my company could do something similar.

5. The game of it all.

It wasn't that long ago that "gamification" was the newest, new thing in customer and employee management. Here, the prizes are nice, but they're not life-changing. (The United program was going to give away $100,000 and Mercedes cars.) Instead, it's more about being appreciated and given a chance to get more rewards. Honestly, it sounds like a game where almost everyone wins.