I'd say by chance and because of a desperate need to find nice and personal Christmas presents!
Most of the times you end up buying very expensive and banal things that, with a good chance, have already been bought by other people for the same recipient: 3 pair of slippers for the poor granny, 2 identical ties for dad, 4 copies of the PUPA make-up kits for your sister (but this is probably something only Italian girls from the 80' remember!)... embarrassing !
And what about more personal items like parfumes, jumpers, underwear etc? Never ever the right size, or colour or fabric!!! So why not going for something unique and very personal as a home-made candle (that by the way doesn't need to be changed in colour, size or fabric!!!)