Coneheads
This wishy washy effort based on an old Saturday Night Live skit pits an alien family on Earth who gradually settle into human life including having a daughter who feels (and acts) more human than alien and doesn't want to give up life on Earth according to her parents' home world plan of Earth conquest.
You'll guess the ending way before it happens and ample opportunity is given to milk the idea in its running time, but a bit of a stretch for the original routine.