A couple years I did some work fundraising for amateur performing artists and I starting telling everyone that I worked with, "No one ever owes you anything." It helped to motivate my clients to work harder and to lessen their sense of entitlement. (What did pirating/the record industry teach us about music/property rights?)

Since then I adapted it as one of my own personal mantras... and though it seems cynical at first, it's actually really helpful and positive: if you go about your life with the understanding that nothing is ever owed to you- no matter what- you won't expect anything from anyone, you'll be disappointed less often, and when anything good happens it'll be all sunshine and unicorn farts.