In the Kuglemass episode I think the single effect is that your never happy with what you've got, you always want more, or you want what you can't have. For example, Kuglemass wasn't happy with his life so he went to Persky for a change. In the end he had wish he wouldn't have went that one last time because he got himself into a big mess he would never escape.
People are always looking for a change. When someone changes their life they are just asking for something to go wrong, of course unless their life is bad and they change for the good. In this story, Kuglemass was not happy with his life so he changed it. He was worried his wife would find out he was having an affair with this woman so he got scared and lost interest in the woman. He went back to his wife and decided he wasn't happy once again, so he went for another change, something happened when he went back and he was stuck inside of this Spanish book for the rest of his life. There was no getting out. The first time should have been a lesson but he didn't learn anything so he had to go back and really screw things up.
People seem to never learn their lessons. Its like if your not supposed to do it then it is that much more tempting to do it. People want what they can't have and once they get it they don't want it anymore. For example, if you see this really expensive car you are going to want because chances are you cant afford it, but if u buy this car you will most likely regret it because the payment and insurance will be so outrageous you will have to work 3 jobs just to pay it.
