Agree on DAWs. Even though I'm familiar with the general concepts, every time I try out a new one (Logic, Reaper, Ableton), it's quite overwhelming at first. You have a pretty good idea about what's supposed to be there, but the sheer amount of knobs and buttons... But once you get in the flow, you quickly find out it has all the information you need, nothing more nothing less, it becomes second nature.
(Notable omission: GarbageBand. It has the opposite effect, it instantly puts you into action, but becomes more frustrating the more you use it.)
Another, maybe forgotten one is Wavosaur on Windows [1]. Great modularity, one can quickly remove cruft that's not needed, or add a lot of data on waveforms when necessary. I admit being a fan of the Classic Windows era UIs, though. :)
A third, also forgotten one from the Win2k/9x GUI era is maybe Waveshop [2], also a great example of keeping things simple.
Funny thing: I used Reaper for years (occasional pro-level radio production), then had to switch to Pro Tools because of studio demands. Afterwards tried going with Reaper again, but got really overwhelmed with all those endless possibilities for customization. So... I ended up using Ardour, which was easiest to grasp from day one. Really well thought out and polished GUI. Possibly a great example of why it makes sense to have a subscription/payment based, non-free open source project.
Oh, and Audacity up to version 1.26 was also great. After 2.x, it started to add bloat IMO. I remember Eric S. Raymond highlighted it as a great example of modular, unix-y design in "The Art of Unix Programming" [3].
Logic Pro X really impressed me with its accessible UI. Yes, there are a lot of functions, but they don't get in the way, and the important ones are fairly discoverable. Reaper, OTOH, not so much. Its routing is ... flexible, but unfortunately also in places where it doesn't matter, or even gets in the way.
(Notable omission: GarbageBand. It has the opposite effect, it instantly puts you into action, but becomes more frustrating the more you use it.)