YouTube Anti time waste 作者： Attire99

save time from getting distructed by youtube suggestions
which usually big waste of time
watch what is needed, then head off :)

youtube auto loop videos,
hide suggested
hide "For you" videos
replace main page with simple search box
and more

the following addons seems to be more advanced than mine:
https://addons.mozilla.org/en-US/firefox/addon/youtube-recommended-videos/
https://addons.mozilla.org/en-US/firefox/addon/block-youtube-feed/