Seen in the wild:
... WHERE substr(amount,0, 1) != '-'
If you wanted to query a table of monetary transactions for any refunds (i.e. where the transaction amount is negative), how would you do it? Perhaps you’d think about avoiding problems that might occur if the default number format were to change, hm?
(before you say it: no, there is no index on amount, so it wasn’t a misguided attempt to avoid an index access path…)