A general golden UX rule is to never cause layout shifts on hover events, preventing this sort of thrashing.
Unfortunately, Google/YouTube and others have lost the plot and no longer employ good UX professionals in their flagship products.
Unfortunately, Google/YouTube and others have lost the plot and no longer employ good UX professionals in their flagship products.
Short-sighted optimization for engagement is the cause of an overwhelming majority of the problems on the Internet.
It feels so fantastically “pushy” to start playing the audio of some random junk that just happened to be under the selection reticle.
They helpfully added a configuration option to turn this behaviour off, which is a tacit admission that it’s a misfeature that users want to disable.
It does nothing.
The videos still play.
But yeah, hover is just for info about the thing you're about to click, not pretending I've already clicked it when I haven't.
The stupid thing about Youtube is that sometimes a video starts playing on hover, in the thumbnail and without sound, and then I actually do click it because indeed it is something I want to watch, and then I miss the first couple of seconds because it's already shown those, with the sound off. It's just the most bizarrely stupid UI decision I can think of.
Sites like Booking.com do this to the umpteenth degree.
This was such a common thing to test for in fluid layouts under AIR/AS3/Flex, or any previous lingua franca where you had to design and code your own rollover effects or web components. So much is elided in mouseout and mouseover. Really, unless you've coded those events in a stack from movements, you don't understand what they mean. In any UI, it's the #1 thing you have to watch out for (along with stuck hovers, accidental focus and things like that). Mouseover/out depend on the entire screen graph as well as timing to establish user intent. Thrashing the whole UI off that because you shift the layout is the worst example of how to do it wrong. Amateur hour.
I weep for this new generation of web developers. So much more complexity, leaving little time for studying and nailing well-established HCI principles, which used to be less of an issue when web was simpler.
What vexes me is that I learned these principles from companies like Google in the first place.
I have literally no idea what people are learning now in academies before being set loose to do front-end work, but obviously it's mediated through so many libraries that they haven't had much time to consider what's going on behind low-level user interactions and load sequences.