A friend should enrich your life, not make your life harder or hurt you. You should enrich a friends life, not make their life harder or hurt them. Does that help?
Are there any? is a pretty wide open area, yes there are....but what?
If a friend tells you something personal about themselves and says don't tell anyone, I think you have an obligation not to tell ANYONE.
If a friend said they killed someone and wanted me to help get rid of the body, I'm afraid my obligation is with the police, not the friend. Who wants friends that kill people.
You are not obligated to lend a friend money but it is nice if you can to help out, just expect it to be a gift. Much easier to borrow then to pay back. Who wants friends that will take your money and not pay back.
You are obligated to yourself first then to a friend, if you can live with it.......go for it.