I have formulated a theory about TV theme songs. Well, actually, other people formulated it long before me, but here it is anyway: any show, no matter what happens in the title sequence, can be made to seem heartwarming and sweet if you add a heartwarming and sweet theme song.
For example, look what happens when I take the main title of the British The Office and plug in the Full House theme song. Suddenly Slough seems like a really adorable and uplifting place to work.
And like the "Family Affair" theme, it works fine with Buffy:
Other suggestions welcome.