I believe that chewing food with an open mouth, to slurp (soup) or to smack is not a normal behaviour here in CZ. A public place or home, such a lack of basic table manners is generally considered to be disgusting and rude to the people you share a table with. I don't think eating a dumpling with hands is comparable to eating with chopsticks in a Chinese restaurant. I bet that to many people in Czech Republic, it's more like a Caucasian using chopsticks to eat western food in a western style restaurant in a western country - really weird at least. I can easily imagine some other customers staring at the people eating this way, thinking "These stupid Americans really don't have any manners, eating like pigs even in public." and strengthening their view of Americans as obese, rude and loud morons. I would be definitely interested in a thread focused on such differences between Czech Republic and other (English speaking) countries. Some are well known - like not taking off one's shoes at home, doors having doorknobs instead of door handles or having a toilet bowl and a bathtub in the same room (which unfortunately seems to have become common even here for new flats). But some things are not that easy to discover.