I know that this very biased and subjective but please hear me out. And if it doesn't make any sense to you then please help me improve my question.
To give you a very recent example from the beginning of this week: I opened the process builder with only a couple of flows, opened one of them, and then tried to edit one of the elements there. When the process builder should actually open a modal dialog it just did not. I clicked maybe 10 times or so while always waiting for it to react. Nothing happened. Then I tried to do anything else - clicking e.g. the menu on the right side. Still nothing. After 60-90 seconds (I'm not kidding you!) 10 modal dialogs appeared on top of each other. I closed all of them one after another - then I got a hardcore exception, telling me that everything broke and that I should reload the whole thing.
While this was my most extreme example to date this is roughly what always happens if Lightning breaks. I cannot click or the clicks behave in a weird way - then the UI goes apeshit. And it all closes with a nice error that basically conveys: "Please press F5 to fix everything!"
Even if it doesn't go so bad - the experience (and performance) sometimes is extremely depressing. For example - I open up maybe 5-6 tabs (using Chrome) that are utilizing LWC at the moment. Memory usage goes up and the browser becomes slow and stops responding. Sometimes these tabs even crash. When I'm done and I close them all everything goes back to normal. As a human that has a serious problem with tabs, often opening hundreds of tabs at the same time (which is a completely different story), I'm just baffled how just a few tabs with Lightning components can break my browser so badly. And this even happens for Salesforce websites (Trailhead, etc.) that utilize LWC here and there (although not as badly).
Somehow I thought these were just my personal issues because so far I do not have much experience with LWC yet - but since I just had this huge problem I spoke to some of my LWC dev colleagues that are way more experienced than I am. Turns out - they have the same problems. Just not as severe as I have.
So I'm really wondering: Am I doing something wrong? Is there something fundamentally not quite okay-ish with LWC? Are the problems I should know about? Because - how can I trust LWC and components I develop if not even the own Salesforce UI is free from severe problems and/or just fails spectacularly?
I really hope some people with way more experience than me can shine some light on this.