The tremolo is a great example because of its simplicity - we have seen many examples on this forum of people that have either a very inefficient one and are still seeking it and others that have found it and is now available on request - fast and smooth. How many have one that is on a knife edge? Quite good but not fully matured? I’m a bit like that - I can get it to 200bpm 16ths smooth at times - I know when I do it, feels great. But sometimes I max out way shorter or its fast but not smooth? I have experimented with both very playful relaxed attempts and monitoring to hardcore militant practice both with similar results!
I have never found anything on guitar easy or smooth that I could turn on when I wanted…not for the lack of trying. I know what it feels like when its good, but I don’t feel what was different. For someone that has one or more types of motions down - can they actually go back to being crap if they don’t pay particular attention to it, or is it just a given now?