Defintion of Complacecny

Websters dictionary defines complacency as
1: self-satisfaction especially when accompanied by unawareness of actual dangers or deficiencies
2
: an instance of usually unaware or uninformed self-satisfaction (Webster's Dictionary)

Another definition would be
complacent - contented to a fault with oneself or one's actions; "he had become complacent after years of success"; "his self-satisfied dignity"
Word Net Search from Princeton

I personally would describe it as grown comfortable with surroundings and unaware of reality.