Youtube is used horribly by advertisers. Don't make a video ad that plays before the content that people can't wait to click Skip. Just make a video that's entertaining/informative and post it to youtube. People will share it for free and watch it willingly.
I work at an advertiser. Most so called "viral" ads we've researched involve significant levels of paid impressions before they got to a "viralable" level. There ain't no such thing as a free lunch.
Also it's significantly difficult to make a highly entertaining ad as well as convey your product benefits/superiority at the same time - strains creativity of the ad agencies though some are adapting faster to the online ad formats more than others.
At the end of the day all those "emotional equities" that highly engaging and emotional ads convey have mainly a role in creating a positive image around your brand - making people actually buy is very difficult without actually conveying your product's value and benefits.
Sarcasm aside, sadly, if you build it they will come doesn't particularly work.
Say you're made a new flavor of ketchup. Your product tests show people love it much better than anything else in the market. Arguably you are adding value to those people's lives with it.
Now it won't sell at all and recoup your investment and arguably actually add value to people's lives unless they know about it and try it - hence advertising.
You make it sound so easy. You should be in advertising so that you can show them how easy it is. The truth is good ads are hard to come up with and the ones that really strike gold go viral [1]. I'm content that I can at least skip them after 4 seconds.
