Tescos seem to be remarkably bad at packing one's whole order in full and without bits of other people's orders. Thus, some deliveries you find you are missing a few items; you have lost the Tesco lottery, as some other person has your smoked salmon... however, you just call Tesco and get a refund.
Now, somewhere else there is a person with your smoked salmon and somebody else's bottle of vodka, but they are missing some toilet paper; they call Tesco and get a refund on the toilet paper, but keep the other stuff they didn't order; they have won the Tesco lottery.
The fun thing with the Tesco lottery is that the only real looser is Tesco.
2. "Damn it, I lost the Tesco lottery! Where's my wine, coco-pops and steak? All I have is this Pepsi I didn't order. Oh well, I'll keep the Pepsi and get a refund from Tesco on the missing stuff."