1. reimu! marisa can do float float on the water! yu~ amazing! reimu want to see it! 2. ok! watch it easy from there! yuyuk!? 3. hatless marisa drop dead easy! yugee!? 4. yufu~ can take easy now~~ but why!?
You see, when this Reimu was a koyukkuri, her mother Marisa was killed by a hatless Marisa looking for a replacement hat. As the father Reimu had died earlier (was probably caught by Remiryas while hunting for food), the little Reimu and her sisters were left alone.
Little Reimu tried to take responsibility and gather food for her sisters, but she couldn't provide, so eventually they all died. The Reimu blamed the hatless criminal for that, and grew up to hate them with all her bean paste.
Later, when she grew up, she herself was attacked by a hatless yukkuri, she killed it in self defence.
And now, seeing the hatless Marisa, the hate and the instinct to kill kicked in.
i hope so, cause otherwise, it takes the stupidness way too bloody far, as it should not even be able to form coherant sentances if it cant even remember that the marisa is still the same marisa just because it dropped its hat (right in front of it, and not even while it blinked).
while extreme forgetfulness is ok in some cases, a simple act that happens right in front of it, with the hat still being visible is just kinda stupid.