I think for me, nowadays, common usually means bad mannered. For example, eating with your mouth open, chewing gum loudly, overtly sexualised public displays of affection, etc. I suppose too, being very scantily clad makes me judgemental!
When my DIL first came down from Hull to meet us she had lots of tattoos and piercings. I was horrified, especially as my son who was still under 18 was not allowed to have tattoos or anything other than his ears pierced if he wanted to live under his father's roof. When DIL tried to get a job in our area, she soon learned she had to take her piercings out and cover her tattoos to stand a chance of being successful. She was incensed and I wondered how she could be so naive. However, many years later, I wonder how I could have been so snobbish and judgemental. Tattoos and piercings don't change the personality; she is lovely, a hard worker, a good mother and a kind person. What more could I ask for my son who is a bit of a picture display board himself now. No amount of tattooing has changed his lovely nature.