No, no, no! In the UK it is not uncommon! People over here are talking shit all the time, often not about anyone.
It amuses me to hear a US citizen use words and pronunciations I know are from the UK, just due to exposure to the BBC. In the US, Hyundai is pronounced "hun-die" or "hun-day", but I have a coworker who is very much an American who pronounces it "high-un-die" because the only time he hears the word is when watching Top Gear.
The Internet makes it difficult to tell which dialect the author is speaking, spawning these arguments and fostering communication between people 3000mi away from each other. That's a wonderful thing. Now if only I could figure out what a curry is and why everyone seems to love it over there.
Though you may encounter the odd person in everyday life who is 'full of shit'.
Such is the British way, we tend to use these as terms of endearment just as much as genuine insults.