PAYDAY 2 is one of my favourite CO-OP games out there and there are multiple reasons why.
First beeing the characters and the "Gang" where everyone has it's own personality.

One beeing that this game never got boring to me and It will never get boring, I can tell you why!

Even though there might be "just" 50+ heists, not counting great custom heists on the workshop, I played every single one of them multiple times and I can still play it without it getting boring or old, you just get better and even faster at it to be honest.

It's completly up to you what you want to do in this game, wether you like loud and action filled combat with heavy armored cops then you can run in guns blazing into a loud heist and kill whatever gets into your line of sight.

Or perhaps you like it more sneaky and stealthy without trying to alert any guards, security cameras or civilians.
By the way I'm counting me as one of the more silent and sneaky persons so I kinda also like the idea of beeing able to sneak the whole deal without anyone noticing.

It never gets boring because you can always try different strategies in stealth heists, approach your mission objective from another perspective or just ruin the whole stealth part and do it loud!

You can try out various heists between 7 different difficulties ranging from easy to harder, much harder, overkillable hard, deathwish kinda hard and finally DEATH SENTENCE kinda really kinda hard.

Yeah, hell yeah!

The voice lines of every single character are great, the voicelines of the contractors are incredible, the feeling that you get when you get caught in stealth is.. really ♥♥♥♥♥♥♥ annyoing and frustrating, but you try again and again and voilá!

There you go you just robbed a huge vault filled with diamonds, money and other precious things

Or you just cleaned a whole giant mansion with the owner beeing the most well known drug dealer.

Then there are the skilltrees which are just a massive chunk of 5 different pages with 3 trees each page where you can spend your mastery points and create incredible overkill builds where you literally kill anything within seconds, or you build the ultimate Ninja-stealth kinda build.

The possibilities are endless, oh and did I talk about the... wait nevermind this is getting way out of hand.

You know what, I sincerely thank you for reading through all of this bunched up text about this game.
Now head out there and try it for yourself!