One of them problems with this TV series is that they made Samantha so magically powerful that in order to give her problems to overcome, they are often are compelled to ignore obvious, simple solutions to keep the plot going.
For instance, in this episode she has the man who used to be a frog in her house shooting his mouth off to strangers (about being a frog) and causing trouble. Now, given that she is a witch, there are countless things she could do about this. She could have easily zapped him into an upstairs bedroom and kept him there until the guests were gone. Or, she could have taken his voice away temporarily, so he couldn't talk to anyone. Or, for that matter, she could have temporarily turned him into a lamp and stood him in the corner until the guests had left. But instead, she lets the stranger stand in the middle of her living room and talk crazy about being a frog, not only to the always-suspicious Mrs. Kravitz, but to Darren's boss and his visiting business client as well. It simply makes no sense.
And for that matter, why does Samantha never simply wipe the memory of Mrs. Kravitz, so that she forgets about everything she sees around the Stevens' Ihome? There has never been any rule on the show that witches can't make people forget things. But obviously that would make it far too easy for Samantha to solve most of her problems, so the writers simply ignore that obvious option and make the situation more complicated than it should be.