A Denver man says a simple conversation about unsafe parking turned into a violent encounter with an on-duty United States Postal Service mail carrier, leaving him with serious injuries and long-lasting emotional trauma.The incident happened Friday afternoon outside Neko Ramen & Rice on Colorado Boulevard. The man, who works nearby and asked not to be identified out of fear, says he noticed a USPS van parked diagonally across multiple spaces, partially blocking his own vehicle in a busy parking lot. He says the area is particularly dangerous, noting he had been struck by a car there just one day earlier.According to the victim, when he calmly pointed out the unsafe parking, the mail carrier allegedly responded with slurs and profanity before entering the restaurant to deliver a package. The man says he followed the carrier inside to explain why the situation was dangerous, but before he could finish speaking, the carrier charged at him.The victim says he was head-butted and…..