I really don't know if you've visited youtube only to get the same annoying pre-roll ad over and over again? Well if you have then you should know that it's a systemic issue and erm the easiest way to solve this problem is to pay for YouTube Red and get rid of all the advertising but the easiest free way to do it , however, is below.
When you see the same ad over and over again, hover your mouse cursor over the “i” circle logo in the lower left corner of the video, to the left of the “Visit Advertiser’s Site” link. Click it when “Why am I seeing this ad?”


The video will pause and show the message below, explaining in very broad terms how Google determines which ads to show you. Click the link marked “Stop seeing this ad.”

After clicking, you won’t see this specific ad on any of YouTube’s videos. Answer the next question, about whether the ad was “Inappropriate, Irrelevant, or Repetitive,” and you’ll give Google a little more data…or you can click “Close” without saying why you didn’t like the ad. It’s totally optional.

The sequence is almost identical on the YouTube mobile app: make sure you’re viewing the video in the full screen interface, tap “Stop seeing this ad,” then “Yes” on the confirmation window. Again, feedback on why you don’t want to see the ad is optional.

And that's pretty Much it, it's literally very easy and explanatory and hey, do share the post!! Thanks...
http://youexploit..com.ng/2017/12/intend-blocking-specific-ads-on-youtube.html