Rarely, if ever is it justifiable to rescind or change a post of the day. If you used it pre-maturely, or in an FO, that’s your fault. Don’t punish someone else for your foolishness. There’s a 10 second grace window for accidental uses, but once that passes you’re committed.
If a post could reasonably deserve both a Smiley and a Thumbs Up, choose the Smiley.
If someone posts something you disagree with, a thumbs down is exponentially more potent than an eye roll.
If someone posts something sad, use the frowny. The thumbs up can be used to express support, but can become confusing if used in the wrong context.
(Thumbs up should be used if the post ends on a positive, inspiring, or uplifting note)
Most Yewt posts should be thumbs downed or eye rolled.
The shrug is used to express ambivalence or confusion. It’s an excellent way to neutralize an otherwise humorous post and prevent additional reaction from others.
A Yahtzee is a badge of honor, and is more than the sum of its parts. If someone thumbs downs you to get you to a Yahtzee, it’s not a sign of disagreement, but of respect.
POTDs given sarcastically have the same inherent value as any other POTD. (See rule 1)