If the only traffic you cared about was your YouTube connection, this wouldnt be a big deal. But it normally isnt. Normally youll leave that tediously slow upload to churn away in one tab while continuing to look at cat pictures in another tab. Heres where the problem bites you: each request you send for a new cat picture will get in the same buffer, at the back. It will have to wait for the megabyte of traffic in front of it to be uploaded before it can finally get onto the Internet and retrieve the latest Maru. Which means it has to wait eight seconds. Eight seconds in which your browser can do nothing bit twiddle its thumbs.