Some people say that girls who often go to bars are definitely not good girls. Why?

Bar: A Pub refers to a consumption place that provides alcoholic beverages such as beer, wine, foreign wine and cocktails. Bar refers to entertainment and leisure bar, which provides live bands or singers, professional dance teams and "dancers" performances.

As the saying goes, birds of a feather flock together. Most people who go to bars often are not good people, which inevitably gives people this illusion. Who goes to bars often?