I hate the following on the Interet:
Websites that tell you what resolution to set your screen.
Websites with "Internet Explorer" or "Netscape Now" buttons. **** you, I don't need you to tell me what web browser to use.
Websites that ask you to download and install a font to view the webpage properly.
Webpages that don't run on any browser other than Internet Explorer becayse the designer is too ignorant or lazy to make it W3C compliant.
Websites with MIDI music playing in the background.
People who choose really awful colors for their posts on web forums, like dark blue or dark green on a black background so you get a migraine trying to read their inane crap.
People with 30,000 posts on a forum, 29,000 of which are posts like "lol" or consist of nothing but a smiley.
People who type everything in all caps on the Internet.
People who type everything in huge long rambling sentences with no capital letters, no full stops, no commas etc.
KM.