Disclaimer: some of these may be slight exaggerations.
1. It's never raining or not raining. It's a permanent state of in-between-ness where it's not worth pulling out an umbrella but by the time you arrive at your destination you are still, somehow, soaked.
2. On that umbrella topic... don't bother with one. Unless you want to spend 70% of your time battling to turn it right-way around again after the wind flips it outwards. During this time you will probably dump a puddle of water down the back of your neck.
(Seems like a lot of these are going to be weather-related.)
3. Trade in all your little sundresses and strapless tops and buy 6 parkas. Keep one sundress to wear to the ironic 'beach party' someone will inevitably throw. Nothing says 'aloha' like frost on the windows.
4. Washing your hands at the bathroom sink will be an ordeal in which you wait 40 seconds for the hot-water-tap to warm up, then spend ten seconds playing hot potato with your fingers as you run them from hot to cold to hot to cold so fast that you achieve a nice lukewarm feeling.
5. You will rarely see such a beautiful pink-orange-purple summer sunset anywhere else in your life. It doesn't happen all the time but when it does, you'll know what I'm talking about.
6. Don't fear the Irn-Bru, aka Scotland's national soft drink. It's soo delicious, like bubble gum-flavored crack. (Random trivia side note: Scotland is the only country in Europe where a coca-cola product isn't the top selling soda!)
7. Do, on the other hand, fear the deep fried Mars bar, Scotland's national desert. Blegh.
8. Also don't fear the haggis. Seriously. People like to bag on it, but did you ever stop to think what went into those hot dogs you love so much? yeah. Haggis is delicious end of story.
9. DO NOT, under any circumstances, spell whisky with an 'e'. (Technically I already knew that before coming here but it's still worth repeating.)
10. Either invest in a sun lamp or be prepared to visit your mental happy place A LOT during the winter months.
11. Ignore everything negative you just said because Scotland is the greatest country in the world and you love it really and you didn't mean any of it. :)