I thought I had replied to this, but I guess not....

Our first kitty, CK, used to know when we were leaving on vacation. As soon as the door closed, he'd go poop on the fringe of the oriental in the hallway. EVERY time! That was his show of displeasure.

Our second kitty, Jamara, went bonkers when we got home-ran around like a lunatic.

Our current kitty, Pinot, is VERY attached to us. When we get home, she'll first lay down for purrs and back scratches, but when that's done, look out! She will go NUTS! She runs and runs, then attacks my ankles, then runs....you get the picture. She does get upset when we're gone!