Option, not Obligation
When U purchase a ticket U have reserved an option, not an obligation. If when the time comes to use that ticket comes and U find yourself wary, then choose to let the option expire. It causes no harm to your present-self to do so, because your past-self has already spent the past-money. Your past-self spent past-money reserving the option in the expectation that your present-self would benefit from it, so if your present-self now disagrees then feel free to decline.