Are you fan of new youtube layout or do you miss the old one?
Did you know that there is a way to bring back the old layout? There is an answer to this question and it's called Javascript.

1)
Go to youtube and hit F12 to start console. If your F12 key is not working, press right click on an empty space on youtube page,
click Inspect and then click on Console tab. If it's still not working, go to Chrome settings and Enable Javascript.

2) Once you open console you're gonna see some erros written in red. Those do not concern you. Just click on a new row inside
console and paste the following:

document.cookie = document.cookie.split(' ').filter(o=>o.indexOf('PREF=')!==-1)[0].replace(';','')+'&f5=30030&f6=8;domain=.youtube.com;path=/';

3) Hit enter and you will receive a response log from console.
Press X in a top right corner or hit F12 again to close the console.

4) Refresh the browser and old layout will be back.

Note: You only need to do this once and it will work every time you open youtube.
If you delete cookies, new layout will be back. Just repeat the same trick, copy paste the code above and you'll bring back the old one.