PIE considering how the Reimu forced the whole thing with Marisa, instead of doing something a bit more fair for her and the owner, expect him to not take it easy, again a promise to a pet has limits, and the owner was clearly not enjoying the bargaing, since pets aren't in the same level of human kids like to "accept" a little spoiled tantrum like Reimu's "because im cute and let you take it easy, you do what i say", so yeah, he can't take it easy, but ask yourself whose fault is?
And i don't understand what you meant EndEarth, i kinda don't get the meaning, i always thought this comic was the owner foreshadowing that would happen if he remained annoyed because of the forced transaction and wasn't able to take it easy because of that.