The most dislike manner in public place

What kind of manner will on this the most dislike manner list that we can see in public place while we always can see those teasing about bookworm's dullness?

• Talking aloud in public place in order to get attention.
• Talking aloud to their cell phone as a public announcement to everyone.
• With American High School classroom manner and thinking they are cool.
• Show they are smarter, so they can act in public place to draw attention.
• Acting intimately in public place as they are in their bedroom, no matter they are straight or homosexual.
• Spiting and making noise aloud in public place.
• ..to be continued......let's think more...