Just missed a concert?
Just did some extra chores?
You are COMPLETELY TRIVIALIZING what Frankie had to endure in that episode. Simply missing a concert or working a little harder than usual is one thing. It's another thing entirely for these things to happen thanks to a devious moocher who spends the entire day taking advantage of someone. And since it happened to a character that is already very sympathetic and underappreciated, it was simply hurtful and meanspirited.
"Imposter's Home" is INFINITELY WORSE than "Bendy" ever was. Bendy was unmistakeably evil, but what he did to Bloo and the others is NOT EVEN CLOSE to what Goofball did to Frankie. They didn't get completely abused, overworked and cruelly denied from something they were really anticipating, like it was the case with Frankie.
By the time the episode was over, I didn't AT ALL care about the whole "human or imaginary" story. All I had on my mind was revulsion about what happened to my favorite character, and extreme disappointment towards the entire crew for actually thinking the entire episode would be a good idea. To this day, I still worry that the Foster's crew could potentially slip and create another hurtful monstrosity on an episode like this one.