Correlation does not imply causation

I'm struggling to explain day one of my fair, so I'm resorting to dorkiness:

• Last year I did one big fair and was blown away by how much I sold.
• Last year I did 15 small fairs and was blown away by what a waste of time it was.
• Ergo, large fairs = success.
• Last year's successful fair was pitched at the general populace, this fair is targetted at people with children under 5.
• Target market this fair > target market last year's fair.
• Ergo, success at this fair > success at last year's fair.
• I sold 300+ items last year.
• Ergo, I need more than 300 items for this fair.

This is the thought process I have been blithely following as I've stayed up until 2AM practically every night for the last couple of weeks, churning out garment after garment after garment. Buying more supplies, to make more garments. Slicing and dicing my fabric stash to make more garments. Oh, how proud I was of the size of my stock! 195 t-shirts, 70 pairs of shoes, 38 dresses, 30 rompers, 24 peasant tops, 8 jackets and assorted trousers and skirts. I worried I might not have enough.

But, 'Wait!", I hear you say, 'correlation does not imply causation!'. Big does not necessarily equal success, there are many other variables. Like Scottish weather. Yesterday was blowing a gale. My newly-pretty-but-waxy-residued eyebrows threatened to collect the debris whipping down the street. After dark, the heavens opened to near-Biblical proportions. Arriving at the venue this morning, the marquee shuddered with the gale-force wind. My wheeled hanging rails kept making a break for it until I taped up the casters. Rain permeated the supposedly impermeable ceiling and dripped on my table. Would you believe the Portoloos (that's Portapotties for my US friends) actually blew over?! My rockin' apron was hidden under my winter jacket (and sweater and shirt). In the end, this didn't matter, because I sold five t-shirts all day long. Nothing else. And with the forecast predicting the same weather for the next two days, I despair. If things don't improve over the weekend, not only won't I remotely cover my hiring costs (remember big fairs= big table costs) but I will be laden with more than 300 ready made items and a very small fabric stash...