h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

1) Forgot, when using magic, to be careful exactly what I asked for. If you don't think magic works, just try it when you're not being careful about the possible outcome. This goes in spades for love spells and money spells.

2) Knowing I've had a food allergy for years, bought a packet of sausages without checking the ingredients. Then cooked and ate them, before remembering to check the ingredients, as they didn't smell the same as the time before. Result - one self-inflicted migraine attack and several hours of raving at partner to breathe more quietly.