Good days are inevitably followed by bad ones
Ignoring annoying behavior works great at home - not so great in public
Kids don't like movies, they like A movie, so get used to watching it ALL THE TIME
Favorite food one day = poison the next
Excited, enthusiastic praise works wonders, but the promise of exciting adventures (like going to the pool) works miracles
Looking at pictures/videos of themselves is even better than the favorite movie (and will be looked at/watched with just as much regularity)
There will ALWAYS be days/times you want to throw your child out a window, but they will always be out shined by the amazing moments when s/he curls on your lap and says "I sure loves you" or kisses you good bye and exclaimes "see you later crocodile" or even better, makes up fantastic pet names for you like "Linny Bug" (from my neice Caroline) and "Banaida Lindsay" (banaida = banana, from Evan the 4 year old nephew)
Finally, it's always worth it :)