Most of these aren’t metaphors, btw.
‘metaphor’: a figure of speech in which a term or phrase is applied to something to which it is not literally applicable in order to suggest a resemblance
@galileogirl, @Likeradar and @cprevite‘s examples are actually similes, which are comparisons using ‘like’ or ‘as’.
A good metaphor is something like “love is a rose,” “time is a thief,” or “she’s a rainbow.”
Incidentally, I really like the song “She’s a Rainbow,” so I guess that could qualify as one of my favorites.