The problem is that at a real company, this is very difficult because you have to argue with your product/design team and explain why you don't want to implement [x] feature because it's "too complex". Inevitably they'll point to some competitor website that has the same feature, which makes you look like you're just lazy. It's possible to succeed in those arguments, but it's hard.

It's one thing to convince them not to do some weird scrolljacking, but even something like a dropdown or a popover adds a ton of complexity for responsive sites.