How do I apply the idea that bad faith and self-deception?

The most direct way to practice is through a focused exercise: Select a situation in your life where you regularly tell yourself "I have no choice." Write out the full narrative you use to explain why you are stuck — every constraint, every obligation, every reason this situation is simply given. Then rewrite the same situation using only active-voice sentences that begin with "I choose" or "I am choosing." For example, "I have to stay in this job" becomes "I am choosing to stay in this job because I value the financial security it provides more than I value the discomfort of searching for alternatives." Notice the emotional difference between the two versions. The second version may feel heavier, more uncomfortable, more exposing. That discomfort is the weight of acknowledged freedom. It is what bad faith exists to avoid.

Common pitfall: Weaponizing the concept of bad faith against others — telling your partner they are "in bad faith" for staying in a job they dislike, accusing a friend of self-deception because their values differ from yours, using Sartre as ammunition in arguments rather than as a mirror for your own evasions. Bad faith is a first-person diagnostic tool. The moment you use it primarily to judge others, you have enacted a new form of bad faith: pretending that your own freedom is well-handled while someone else is the one evading. Sartre himself warned that the "champion of sincerity" — the person who demands that others be honest about themselves — is engaging in a form of bad faith that is just as evasive as the dishonesty it attacks.

This practice connects to Phase 75 (Existential Navigation) — building it as a repeatable habit compounds over time.