I miss the days when I only had to pay once for a video game

These days, game companies and developers are monetizing their games to their full potential. It's not enough to sell a game just once: If you don't sell extra content, you could be leaving millions of dollars on the table.

We're seeing this kind of upsell everywhere, including big name titles like "Assassin's Creed: Unity" and most recently "Mortal Kombat X."

So, why is this happening? Because it works.

It's super effective

More likely than not, you've paid for an add-on in a video game. People do it all the time, for mobile games like "Candy Crush" and "Clash of Clans," two of the top grossing apps in the App Store. People love spending money on downloadable content because they love the game and want more of it.

Personally, I've had a years-long addiction to "The Simpsons: Tapped Out," and I'm constantly tempted with opportunities to buy exclusive content or get ahead in the game by paying actual dollars.

In some cases, game companies create and sell extra downloadable content out of necessity: To keep the business running, and to give customers more content for the games they like to play. But in many cases, selling extra content has been twisted.

Today's video games have Hollywood-esque budgets - some of them, including "Grand Theft Auto 5" and "Destiny," have hundred million-dollar budgets. But once these companies recoup their costs for making and marketing these games, they want to make a nice profit, too. These are businesses after all.

But game publishers face a few constraints: Console game prices have been locked at $60 for awhile - it's been a longstanding fear that consumers won't be willing to pay more than $60 up front for a video game. And even if you sell millions of copies of your $60 game, not all of that money goes to the game company. These companies get even less money when the game is eventually retailed at a discount. And it certainly doesn't help that the world's largest game retailer, GameStop, makes more than half its profits on used game sales - sales that publishers see no money from.

So, to be profitable, game companies need to milk their games for more money - but they can't raise the price of the game itself without risking backlash from consumers. That's where microtransactions and downloadable content come into play.

Good for business, bad for customers

In recent years, we've seen companies take content they've already developed for their games and put it behind a paywall, asking for $20-$30 to access the "season pass." This is even happening with the newest "Star Wars" game coming later this year, "Star Wars: Battlefront." People are criticizing Electronic Arts for removing content from the original game only to sell it back later as downloadable content you have to pay for.

The problem with microtransactions and DLCs is that it makes the initial standalone game feel incomplete by default. It forces people to constantly shell out money just to play the full game they wanted to play. So while these practices work, they also hurt consumer confidence, and games in general.

Hopefully big game makers use these tactics less frequently, and people will vote with their wallets and stop paying for them.