Derek Sivers argues people should choose beliefs based on usefulness for action and emotion, not objective truth, using short fables and personal reframes.
The stories we are told and tell ourselves are fictions, not facts, and seeing that dissolves their grip. A friend who says 'sorry, I can't right now' hasn't rejected you, and a city isn't objectively good or bad; it's what you make of it. Doubting your first story leaves you free to choose a story that serves you better.
Most of what we believe can't be proven either way, so the better question to ask of a belief is whether it helps you, not whether it is true. Believing in an afterlife, for example, can guide your actions or ease your fear of dying, even with no proof it exists. Once you see you already pick beliefs this way, you can do it on purpose to boost motivation and act more effectively.
There is a gap between something happening and your response, and that gap is where you choose how to see it. A first reaction like 'this is a disaster' feels true but is only one perspective, an obstacle to get past. Many people in jail are there because they acted on a quick emotional impulse instead of using that gap.
How you see a situation shapes the plan you make and the actions you take, so success starts with the viewpoint you choose. Seeing things a certain way can put you in a mindset that spots opportunities others miss. Choosing that viewpoint on purpose is a practical tool, not self-deception.
Only physically observable things are necessarily true, things any creature, even an ant or an octopus, could see and agree on. Nearly everything we talk about lives in the mind, and those things are never necessarily true; they are perspectives that feel like truth. 'Not true' here doesn't mean false, just not true for everyone, everywhere, always.