All the 'fries' and 'isms' are the result of person after person imitating one another (usually from people they admire). The catalyst is the grade school mentality inherent in this, not unlike the now outdated California Valley Girl speak of the 1980s.
I'm from the US and I'm thankful that most mature, well educated adults don't speak like that here. Idiosyncrasies such as these appear to affect the younger set and they are popularized by the media in TV commercials, Sit Coms, etc.
Fortunately, all these fads have a short shelf life because they are soon replaced by new and even more annoying ones. 