Onee-chan Came
Who doesn't want to get an older
step-sister who is infatuated with you?
I suppose being a 3 minute anime makes it watchable, much like that anime with the kid who looks like an adult so everyone keeps confusing him as a pedo (Recorder to Randsell?), because expanded into 20 minutes like in...
Engaged to the Unknown
... it really does become a bit insufferable after a while.
Also, in a post Non Non Biyori world, I have a bit of a hard time with precocious children nowadays:
Something about how she acts just doesn't seem genuine. Although I suppose it's because she mostly exists only so that the older sister (in law) can try to molest her rather than anything else.
Also, the red girl is "fat". Oh anime!