Public drunkenness, foul language, and excessive imprudence on social networking websites, such as Facebook, are some of the examples of this increasing bad behaviour.
Model agent Tanya Powell, who teaches manners and etiquette to 500 students a year, has said that the public indiscretions of sporting personalities were fuelling bad behaviour in young men.
"Boys want to be like their sporting heroes, and binge drinking is a huge problem - the boys think it makes them look macho," Adelaide Now quoted her as saying.
Powell said that such "bogan behaviour" is also rampant among young girls
"They go out and get absolutely drunk and it looks very cheap and nasty. And it doesn't help when they drink from bottles like a man," she said.
Apart from using foul language in public, youngsters have also forgotten manners like "please and thank you" and the correct use of crockery and cutlery, she said.
Finesse models director Brigette Mitchell said she taught her students not to be seduced by the exploits of celebrities such as Paris Hilton in teen magazines.
"Some of these famous people are just not good role models," Ms Mitchell said.
She warned students to be mindful of what they posted on Facebook, as it is "basically for public viewing".
"To a certain extent, some bad manners are simply part of being a teenager and rebelling, but there are definite dos and don'ts," said Mitchell.
"Because social networking is the young people's domain, they actually have to be the ones to work out the rules - and (yes) the rules are pretty poor," said Dr Mia Stephens from UniSA's School of Communication.
She added: "And they are only letting themselves down when they post photos of the public drunkenness they are copying from the sports stars. Lack of chivalry is one way of putting it . . . lack of social skills is another."