Diva Room present problems?

So based on the list of items that characters like, Miku and Luka love the Sketchbook - so why is it that Miku got mad at me and I lost part of the heart instead of gain? I remember in other games, you could give the same items to the characters over and over and they would either be neutral or increase depending on how many you give them. If it's because I gave her Sketchbook too many times (for obvious reasons, it's necessary to do it 15 times...), then how the heck am I supposed to ever get all 15 if she keeps refusing to do the event? This also happened when I gave Miku Leek Shish-Kabob for the 1st time, and she's supposed to like it! Instead, she rejected it, what's going on with my game? :(


Edit: Ok, now she's happy I gave her yet another sketchbook... Miku, why are you being so bi-polar? ;_;

 

I noticed even while switching, or trying to give them OTHER THINGS that they like that i've NEVER given them before because I just attained, they still get mad. -_- This is starting to get upsetting, because it makes leveling a lot harder than it should be....

 

So, i've noticed something - don't give them too many things that they like. Instead, give them something they LIKE, then something they are NEUTRAL, and repeat... it hasn't failed me yet in the past 10 attempts (although I seem to be stuck at about 7 sketchbooks, because they keep doing repeats... and that last calli paper is being difficult too).