As much as I do miss the context menus and nested drop-down menus of the old days, not all of Modern UI design is bad. It's making computing more accessible to people who didn't have the insight or intelligence necessary to figure out the (frankly) user-unfriendly design decisions of the past, which were mainly made because screen space was a premium back then.

At the same time, though, there is a distinction between normal mouse-and-keyboard computers and touchscreens, and I think that UI design needs to be considerate of both sides of the coin at least until one side no longer exists. That means that if a user doesn't have a touchscreen, they should remove some of the flashiness and make the buttons/menus a bit smaller. As I read somewhere (can't remember where), "With a mouse we can be precise, because we aren't jabbing at a screen with a fleshy appendage in the hopes of pressing the right button because there's no room on the screen to put space between them."

Personally, as far as websites are concerned (I don't have much experience with desktop UI design), I think that Twitter's Bootstrap CSS hits a nice comfort zone between large, touchscreen-friendly buttons on small screens and smaller, mouse-friendly buttons on large screens. Their margins and stuff are still way too big for keyboard-and-mouse users, but they do allow end users to tune the CSS instead of forcing them to use the library as published.

I have to move my hands and fingers further

I assume you are talking about mobile. In this sense it's not something really easy to get rid of. Mobile, despite having unusually high resolutions, has very little real screen size - so designers really have to come up with clever ways of letting you touch, twist, pinch the screen, etc. and even having lots of menus for complex applications because, well just one menu doesn't really fit the screen anymore, leading to a much higher click ratio. There is no 108-key keyboard to map keys to. Tablets have more screen space but mobile devs must design for both.

This is the basis of the problem and there's not much getting around it. Most minimally complex mobile applications are hard to use that way, even if most people just accept it as being normal, while we professionals know they're actually pretty awful. I absolutely have seen interfaces that are much worse than necessary as well for mobile, like those ones with huge floating buttons right in front of your scrolling content - but that's just terrible design as we have in desktop apps and websites as well.

full of animations, it becomes more and more tiresome to use it

I disagree with you here. Maybe not for us power-users but for most people pretty animations and transitions makes for a better experience. Again, it's entirely possible to overdo it but then it's a case-by-case issue, not a a widespread one as far as I'm concerned.

skruf@voat-desktop:~$ man man