For many years I have had Flash issues with skipping, stopping and not playing despite a fast 20 Mb DSL or cable connection. I know Apple hates Flash too.
In layman’s terms - why is it so bad?
Feature creep, in my opinion. Each new version of Flash had to be backwards compatible, but new versions with new features needed to be put out regularly so that Shockwave / Adobe could continue to pull in revenue selling Flash development software. Eventually it became a big bloated mess.
I want to second feature creep. I suppose this is more a IMHO than a GQ answer, but after following them for decades, it’s at least an educated guess.
Flash used to be relatively lean and mean back when Macromedia first made it, along with their other products like Dreamweaver. Then Adobe bought Macromedia, made each version of their software successively more, um, featureful… and bigger, and slower, and less stable.
For as long as Adobe’s been around, their products have had typically more features than their competitors but at the expense of speed, ease-of-use, and stability/security. And they focus far more on making new versions than optimizing older versions, fixing security issues, etc. And the sad thing is, I guess it worked – the market certainly supported them through the years.
The curious thing is, why do only some people report problems? I haven’t had problems (well, not often, and then it is probably YouTube’s fault; I assume YouTube is the site you are using to view videos). That makes me think it is either the server or your internet connection that is causing it to skip and stop. Also, note that the speed of your connection is meaningless if the server can’t keep up with it (I have had sites with Flash games where the server is so overloaded there are constant problems, but Flash or the game itself isn’t at fault, as evidenced by website errors outside of the game).
I’ve read anecdotal claims that Flash seems to perform OK in it’s ActiveX Internet Explorer plug-in guise, but is markedly worse anywhere else.
also, in the moble realm, things that use Flash for e.g. animation or games use CPU-intensive vector drawing which is likely to run very poorly on the weak ARM processors used in phones and tablets.