Am I the only one that absolutely hates the term 'buttery smooth' or any similar metaphor? I don't know why, but it really grates on me. I don't want my phone to be buttery; I want it to be responsive.
There is actually an XDA thread on this very matter

As a non-native English speaker who studied British English, I think it's just a silly Americanism (but I might be wrong). A bit like massacring the word "awesome" or "literally", which really gets on my nerves...
On topic: why on earth would you play a video in a ridiculously small window while you are browsing on another part of the screen? Surely phone screens are too small for this kind of multi-tasking?