Behaviour is important
Behavior is the most important thing about software. It is what users depend on. Users like it when we add behaviour (provided it is what they really wanted), but if we change or remove behavior they depend on (introduce bugs), they stop trusting us.
User akan suka jika kita menambahkan fitur-fitur baru, apa lagi yg mereka inginkan. Namun jika kita menambahkan bug atau mengubah perilaku awal yg mereka tergantung padanya, user akan berhenti percaya.