Cutesy. The 'Amazing Stories' often reflected the upbeat, 'family friendly' fantasy perspective of Steven Spielberg. This episode is a fine example of this.
A nerdy teenager learns that he must abandon everything he knows, including his girlfriend, and travel with his parents back to their real home; another planet. Thus fairly typical, 'all-American' situations (adolenscence angst and the pains of moving) are giving a creative science fiction bent to them. They are also giving a happy ending.
Yup, it turns out that the girlfriend and her parents are also space aliens, from the same planet, returning home as well. Yes, some of the special effects have not aged too well, although I can recall being amazed when this episode originally aired. Yet, you are interested in the characters, you care about their challenges and are glad that things end on a happy note.
At the time, I recall being a bit disappointed that we really do not get to see much of the advanced alien civilization.