Folks are usually about as happy as they make their minds up to be.
What Lincoln captures here—and what separates this from mere "think positive" cheerleading—is the *deliberateness* required. Happiness isn't something that happens to us or something we discover; it's a choice we actively defend, moment by moment, against the thousand small grievances that clamor for our attention. A person stuck in traffic who decides their commute won't sour their afternoon isn't denying reality; they're simply refusing to let circumstances have the final say in how they feel. That's why the quote lands differently when you're actually *doing* it—when you realize that maintaining happiness requires the same discipline athletes bring to their training.
“Never let the future disturb you. You will meet it, if you have to, with the same weapons of reason...”
Marcus Aurelius“For every minute you are angry you lose sixty seconds of happiness.”
Ralph Waldo Emerson“Between stimulus and response there is a space. In that space is our power to choose our response. I...”
Viktor Frankl“We suffer more often in imagination than in reality.”
Seneca