cow knows not what her tail is worth (till|until) she has lost it
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used to imply that people often do not recognize the true worth of something or someone until it is lost or no longer available
The origin of this saying is rooted in traditional folk wisdom, with versions of it appearing in different cultures. This proverb reflects the tendency of individuals to take things for granted, whether it is a possession, a person, or an opportunity, only realizing their true value once they are lost. It serves as a reminder to appreciate what one has before it is too late.
- Susan failed to appreciate her parents' support until she moved out on her own.Only then did she realize that a cow knows not what her tail is worth till she has lost it.