If you ever worked with Blogger, sometime you will encounter some stupid label which was labeled before you. However, labeling using Label management on Blogger, will lead to more stupidity because of Blogger’s Bug, very nasty bug.
Sometimes, if you just select all, or check all the articles, you will labels those checked articles, for example with “FUN”. And as you can see, the label “FUN” FAILED, because it’s “applied to 0 posts”.
My suggestion, if you would like to labeling Blogger’s label, don’t user their “SELECT ALL” and “CHECKBOX”, because it will annoy you. Luckily, they have undo facility.