I didn't much care for Helen after the first ep or two that she was in. When she and Andy first got together, she was practically a feminist! She didn't know how to cook leg of lamb, preferring frozen dinners, and she was not planning on quitting her job at all if she got married. Barney was outraged! I don't know why they changed her.
My favorite ep is the one where the spoiled city kid comes to town. I love the conversations between Andy and Opie about how much Opie's allowance should be and whether or not he should have to work for it. Opie throwing a tantrum is hilarious, too.