I started noticing how sometimes youtube just seemingly refused to load fully on my phone. I thought it was just my crap internet. But since I use Iceraven, a fork of firefox, it seems that may be why.

In addition to the fact that I remember this happening several years ago, I'm pretty sure this has been an issue for a while. When I decided to exclusively use Firefox about a year ago, YouTube as a whole would load slowly and it still does.

And I hate the fact that Google knows that they will benefit from this because, unfortunately, a majority of YouTube users are sheeple.

Once upon a time, Google wanted to kill the user-agent.

The YouTube viewing experience on FF is terrible. I have premium no ads and still manage to break the interface occasionally by clicking a new video or seeking the video playing.

Does not happen for me Safari or Firefox.

Any extensions you'd recommend for having Firefox spoof chrome?

Not trying to defend Chrome here as I dislike their other behaviours, but just from what's presented in the video, an alternative explanation would be caching. That is, when the reloading is triggered by the switch of user-agent, the cache is reused and thus a shorter load time.

To exclude this effect, the user needs to either

1. Spoof the user-agent and at the same time clear cache (you can disable cache when reloading through the developer's tool), or
2. Clear cache, spoof the user-agent to Chrome. Load page, disable the spoofing, reload.