What's the human behaviour called that often makes us warp realities to appease another?
This is called optimism bias:


  ... a tendency for people to overestimate their likelihood of
  experiencing a wide variety of pleasant events, such as enjoying their
  first job or having a gifted child, and somewhat underestimate their
  risk of succumbing to negative events, such as getting divorced or
  falling victim to a chronic disease.


Optimism bias is a type of self-enhancement:


  ... a preference for positive over negative self-views.


and positive illusions:


  ... unrealistically favorable attitudes that people have towards
  themselves or to people that are close to them.