I met a Gursikh who works for Heathrow Airport who shared a story about his workplace with me. He said that one day a white non-Sikh English colleague asked him, "You are Mr. Singh because you are a Sikh. But today I met a man who has his hair cut and is clean-shave who said he was Mr. Singh as well. I am confused! Can you please explain."
The Gursikh gave the reply, "There are 3 types of Mr. Singh. Firstly, a "real Singh", secondly a "shame singh", and thirdly a "name Singh". The Gursikh explained a 'real Singh' is one who practices Sikhi in word and deed. A 'shame Singh' is someone who although wears a turban, but goes against their religion by trimming their beard or drinking alcohol etc. A 'name Singh' is someone who is from a Sikh heritage and has no Sikh identity.
The next day, the Englishman comes up to the Gursikh, smiled and said, "Today I saw a shame Singh on the bus." Waheguru.