Mary Worth
I'm not an advice columnist and I haven't read anything like Dear Abby or Ann Landers in a very long time but if a person who you have already given advice to keeps writing back, maybe you aren't very good at giving advice.
"I can't decide between two jobs."
"You should make a pros and cons list."
"I made a pro and cons list. Still don't know what to do."
"Well, what do you think you should do?"
"You're bad at this."