Denial works by the mind refusing to accept something that is often quite plain to see.
An example might be someone refusing to accept that a friend of theirs is a back-stabbing bitch, because to do so would mean they have to accept that their own ability to judge another person is flawed.
Where an important aspect of someone's identity is built on a belief about themselves, such as being better at something than they actually are, then denial may occur to prevent that structural belief being fundamentally harmed. For example, children have been known to experience visual hallucinations (e.g., not seeing something in front of them) to preserve the image of a parent as well-meaning or kind.
How denial impacts BDSM motivations
For some people, the real reason or reasons they are attracted to BDSM is unacceptable. Someone who is brought up in a conservative household may have serious emotional or psychological difficulty with the idea that they like or need to be hit by their partner, or that they like or need to hit their partner. Or, a woman brought up with feminist ideals may have trouble subjugating themselves to a man.
What can happen in these cases is that instead of embracing their real attraction to BDSM, they may unconsciously look for something more acceptable and proclaim that as their motivation.
This has a big impact on their potential satisfaction from their activities due to diminished engagement. Instead of devising and executing scenes which are designed to meet their real wants and needs, they instead do scenes designed to satisfy the wants and needs they claim to have. This means that what they and their partner do will never really hit the spot.
Here are some examples of misdirected motivations involving denial: