I came across this phrase in this ALearningADay blog post. It conveys an important philosophy very succinctly.

Attempting a half marathon without the proper fitness routine will only end in injuries and demoralisation. Likewise, whether we want to achieve a goal, make changes in our routine or modify some behaviour, we have to meet ourselves where we stand now. Setting realistic expectations assures a higher chance of success by eliminating the biggest mental challenge – disheartenment.