Why is Matt upset with Celia at the beginning of the story?

Matt is upset with Celia because yet again, she is leaving for work and he’ll be left locked up alone in the house all day. Matt is curious about the world outside that he has only interacted with by way of peering through the window. Celia would never allow him outside because it is unsafe for him. Matt does not know that he is a clone, purposefully lab-manufactured to provide El Patron with a replacement heart in the future. However, humans, and more so, those in El Patron’s household, loathe clones and often go out of their way to harm them. For this reason, Matt is put under the safe custody of Celia, a cook in El Patron’s house.
He is finally discovered from his safe hideout and momentarily endangered in the hands of El Patron’s people. El Patron saves Matt and accords him a respectable life, including an exclusive bodyguard. Matt finally escapes his fate as El Patron’s heart donor and moves to Aztlan.