So, in knitter circles there are tales of the sweater curse. (Perhaps in crochet circles too.) The story goes that if you knit a sweater for someone you are dating, the relationship will end around the time you finish. So the knitter is (assumedly) broken-hearted and either in possession of this sweater that is now one more physical reminder of this relationship, or left to ponder that all that knitting is now off with someone who doesn't deserve it, or to possibly wonder if they hated the sweater that much. Supposedly marriage inoculates one from the curse. (My favorite part of the Wikipedia entry about this is this quote: "No controlled studies have investigated this phenomenon, and the available evidence is largely anecdotal, which is generally of low reliability due to cognitive bias. Particularly important in this effect may be confirmation bias, as knitters may remember breakups more clearly after giving a hand-knit sweater, which represents a significant investment of money (typically over $100), effort (~100,000 stitches), time (as much as a year) and romantic imagination."
However, there is a solution (other than first securing marriage or choosing not to believe in curses, which sure, you could also do). One woman has a sweater imbued with chili which will then cause the recipient to itch and burn. That will show them.