If you're in the business of "doing free services so you can skim GB's of data from users" or you "sell wholesale data collected without notice", the EU doesn't want you.
If you're doing a good job of keeping user data private except at the direct request of a user in a plain-language direct permission, then you're doing a good job to the GDPR. Slipups happen, and as long as you do your best to stop the bad thing, limit the breach, notify users, and be a good steward for their data, then it's all good.
As a US citizen, I try to make a point to only work with companies that adhere to the GDPR. I know they don't have to do so with me. But it tells me their internal processes are set up to respect the user's rights. And well, running dual systems for different compliance regimes is a tough sell - its easier to do 1 big system.