Obsessions, not in any particular order...
Olivia -- Butterflies, also ladybugs though not as much as butterflies, Tinkerbell and other fairies, sprinkled cookies at Raley's, saying "S & S Produce," balloons, kitty kisses (that's when she licks you), coloring, Diego (Dora's cousin), animals in general, taking pictures, John the tortoise at the Nature Center, computer games, teamwork!, Puffins cereal, warmed-up juice, Bidwell mansion (we HAVE to drive by it on the way to school), making sure doors are closed when it's dark outside, locking doors, and macaroni and cheese.
Cora -- Dress-up, being dramatic, barbies, Kim Possible, movie night (and movies in general lately), Harry Potter, Star Wars, Prince Valiant (the comic strip), reading books, Peter Pan, playing with her friends, being first, pretty dresses, helping others, princesses and queens, supergirl, weddings (REALLY looking forward to Aunt CC and Dave's wedding by the way), showing off, noodle soup, warmed-up milk, dragons, fairies, blueberry cereal bars, peanut butter and honey sandwiches on wheat bread, and being social.
I'm sure there are probably more that I have forgotten, but it's a start.