"Associate yourself with men of good quality if you esteem your own reputation; for 'tis better to be alone than in bad company." 

George Washington

I believe it is in bad taste to only hang around people who do good. I believe that as long you are just hanging out with a group of people there isn't anything wrong. If and when they choose to do the wrong thing then it is time to make the decision to walk away. If you only associate yourself with 'good' people you may never understand 'bad' people. Maybe there is a reason they're 'bad'. You can just disregard a group of people and just ignore because they indulge in a few questionable activities. If you truly want to be a better person, then make an effort to try to change these people. Don't be burden and judge by what you observe, take some time and talk.