This......this right here.....
But seriously....SEO is important to the success of your blog because it affects how readers find you. Keywords are of the utmost importance, all of your images should have ALT tags (I have failed this challenge already.), and you should check for any broken links.
You can check your SEO by using Google Webmasters Tools and you can check for broken links by using Markup Validation Service.
Basically, if you want to feel like a failure, check your SEO.