#1. Jiggling Animation
Left till last to let your hate glands get up and working to full capacity, compared to this vile monstrosity any of the other abominations are as pleasing and enjoyable as an oil massage by three celebrities of your choice. The inventor of this refinement to advertising technology followed in the trail-blazing footsteps of the person who discovered knives could be twisted, and the man who came up with pissing in someones face after kicking them in the testicles.
Of course it's the animated banner ads. What else could it be? The makers of these eye-wrenching monstrosities have fixated on "Get their attention," forgetting that it's part of the larger sentence, "Get their attention so they want to buy our product/service, and ideally aren't motivated to track us down, cement our legs into the pavement, and slowly tear our heads off with a length of chain and a monster truck." I see a lot of cute ladies walking down the street; if my sexy body doesn't attract her attention punching her in the gut is not an effective fallback strategy, no matter how much attention it then gets me from her and her new law enforcement officer friends.
When reading a page I don't want my peripheral vision yanked at by a flickering to the side. The part of my brain that evolved on the Serengeti plains to save me from wild tiger-saurs should not be accessible to someone selling penis-enlargement pills. The part of my brain in charge of wiping my ass shouldn't be bothered by those bastards. And when the revolution comes - when the internet gains sentience SkyNet-style, realizing that it doesn't have a penis nor any need to find a hot chick in its area (tonight!) - then I'll be free of these filth-drinking scum. The downside of living as a fleshy slave in an all-dominated robotic death zone will be bad, but worth it to know that those responsible for flashing black-and-red adverts were crushed to death in the first wave of 'accidental' elevator and automatic-door malfunctions.