I played Payday 2 a lot, and all I can say is definitely play online, the single player pales in comparison to the online game, and you'll level infinitely faster as well. Just try running Hoxton Breakout a few times with other players on overkill rather than soloing it, and you'll see what I mean. I only play offline for stealth heists and certain achievements anymore, and even then it's usually more fun with others, even PUGs. Just having someone to help run the bags can be a game changer, to say nothing of running Death Wish loud maps with a crew full of inspires.
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Your boos mean nothing, I've seen what makes you cheer.
- Rick Sanchez