Atomic CSS sounds great until you actually try it on a big project and you run into all sorts of issues. Mostly that your html ends up looking like a total mess which slows down the rest of your work, and that it's not flexible enough.
In practice, DRY in CSS ends up making code very hard to maintain. It creates ghost side effects where you change something on one page and break something on another page unknowingly.
With the exception of a few elements that don't really change at all from one page another like buttons, doing a little bit of copy pasting or search and replace between files is easier.
Sure, you might forget to update one page or component here and there, but at least it won't be broken. Better a component is inconsistent in style but functional than broken.
Using a few variables for things like color and spacing can also help minimize this problem.
Keeping most of my CSS components encapsulated and "namespaced" has worked a lot better in practice than trying to make everything reusable and coupled together in ways that you'll forget about when you have to come back to that project a few months later.
The only advantage Braintree has is Paypal support.
I haven't checked on Braintree lately, but the few times I've had to talk to the Braintree support or sales team, they've been very unhelpful.
If your business is not the size of AirBnb they make it clear they don't really care about having you as a customer. And that's even if you process a few millions a year.
If you're outside the US, have fun signing up and jumping through hoops. If you're building a marketplace, your users will have to jump through the same hoops just to start accepting payments.
While Stripe isn't perfect either, they are a lot friendlier and helpful when you speak with them. They also have Stripe Connect and self-signup which makes it much easier to build a marketplace.
I'd rather use Stripe for credit card processing, even if that means dealing with Paypal's bottom of the barrel APIs directly to add Paypal payments. That's how bad Braintree support is.
Maybe they've gotten better and this is out of date, but based on past experience, I don't really care to find out.
Google has some of the worst UI/UX. For all the other great stuff they do, this is one area where they really shouldn't be teaching others but learning from them.
From the barely usable Gsuite admin console to the indecipherable API docs (and developer console), I can't think of a single product where I can intuitively find the setting or option I'm looking for.