Nate's parents and Vanessa's mom.
please add ALL the parents not only the ones you want.

"Letting people down is your forte." ARE YOU FREAKING KIDDING ME?!! Bart is, BY FAR, the worst.

bart is a very bad parent but i agree with what alessandra_28 said also

i think nate´s dad is the worst, pushing him towards dartmouth & blair for his business-deals, blaming his drug-addiction on his son, being charged with embezelmend(?) and fraud, trying to kill himself, than skipping the country, then trying to kidnapp his son & wife to get money from his in-laws...seriousely?
at least lily, eleonor, bart & harold tried (even if they failed st) to be good parents...