Some possible euphemisms:
- A "person of ill repute" is a nice way of calling someone a skank.
- He "passed away" is so much nicer than "he croaked".
- She "tripped the light fantastic" is a gentle description of - wait, what does that mean?! Oh it's about being a nimble dancer! What's so unpleasant about that?! This situation then needs to be described as "disappointing" rather than an "epic fail"!
So when one is out in polite, genteel society it's a good idea to keep a clever euphemism in one's back pocket, at hand, or up one's sleeve as the case may warrant. One never knows when he needs to describe delicately!