Brief thought exercise: what songs MUST you play at a wedding reception?

Little bit softer now ... and a little bit softer now ...

Went to my cousin's wedding this past weekend, so had been thinking about this. Obviously this question is a bit nuanced and contextual, even though it probably seems dumb on face: one of the great things about a wedding is that it typically houses 3-4 generations of two families, so musical tastes are going to differ and you need to get a few different…