Haha I remember there was a day when I was putting adsense on my new blog and spent 30 minutes getting mad that my ad wasn't appearing...It was css and all that....was getting really really really annoyed until I realized I had to turn off my adblocker. And, there was this other time when i was looking at someone's ad placement..I replied saying I couldn't see it so we exchanged a couple PM's where I told the person he did not have ads at all or was so brilliant in blending that I couldn't see it...Couple minutes later, I realized i had adblocker on. I've made a complete idiot of myself at times all due to adblocker