You have probably heard that scripture at 1Co 15:33. That is the one that bad associations spoil useful habits. However, they are not applying it correctly when they mean that people should only associate with those in the inner circle of the organization.
In my experience, some of the worst association I have ever seen was within the congregation of Jehovah's Witlesses. These people have destroyed many a useful habit of mine. For starters, they spoiled my habit of celebrating holidays and birthdays. They tried to go through all my music collection (I had something like 700 records, many of them bought used). Everything they thought was "bad", even if barely, was to be thrown away. What they ended up doing was to force me to set them aside. A number of the songs I set aside got reinstated when I looked at them a bit more objectively.
As bad, all they ever think about is getting me to pioneer. Anything that can be used to force or coerce me to staying out in field circus or go out when I didn't want to for good reason was used. I have had them go on a call that they knew was going to be an hour or more and deliberately make it take longer, starting 5 minutes before I told them I wanted to go in. I also had them start a whole street with 30 or 40 houses, deliberately making it go as long as possible, when I was within 5 minutes of going in (and they knew I had to go in at that time because I had to work that evening). It was all about "saving" that life. How could I think of work when there were lives to be "saved"?
There were too many specious arguments to even mention. The most outrageous of those came from the family that, in fact, wanted me as one of them. Those cockroaches went so far as to tell me that I had no business with the sisters (unless it was one of them, and then it was exclusively to help them in field circus or other theocraptic activity). They told me that the a$$emblies were a foreglimmer of the "new" order, and then told me that I couldn't go by what happened there. They wanted me to donate more money and labor to the Worldwide Pedophile Defense Fund when they had our new Kingdumb Hell built (and they made sure I had pledge forms and volunteer slips for building it shoved into my face). They had so many other specious arguments about everything I should and should not have been thinking about that I would dread visiting them even more than going to the dentist for a root canal.
I definitely think the worst associations can be found among Jehovah's Witlesses. They can't even integrate anything. They want you to waste all your time and money on them, and then they don't want you to enjoy your life. Then they have the nerve to tell people not to associate with the world.
By the way, they also harbor pedophiles and protect them while silencing the victims. They initiate coercion by using bogus authority as a pretext to molest the children, and then they threaten them if they report it or warn others about them. I, for one, call that bad association.