It's funny. As Bewitched fans, on one hand we celebrate the fact that the show didn't rely on non-stop magic effects. The excellent writing and ensemble cast really were enough to propel the show as high as it shot in the ratings, arguably.
But on the other hand, don't we thrill just a bit when a magic effect is perfectly executed? The well-crafted effect can make us believe in magic for a moment or two, if we let it.
Across the entire series, my all-time favorite effect is in "There's No Witch Like an Old Witch" when Aunt Clara tries to dispatch the dinner dishes to the kitchen and the dishes instead shoot upward at incredible speed and break against the ceiling. The technique is as perfect as Marion Lorne's reaction.
Please chime in if you happen to have a "pet" special effect that really makes the show magical for you no matter how many times you see it.