Mental mechanisms are situational.
Mental mechanisms do not have indices of test-retest reliability or of inter-rater reliability.
The distributions of mental mechanisms by age, gender, social class, and intelligence are not established.
Mental mechanisms may be unspoken, or may be confined to a consultation during which money changes hands. Once other people are involved, the possibility exists that the supposed mental mechanisms are part of a relationship, which may have sexual connotations.
Mental mechanisms include denial, dissociation, suppression, repression, fantasy, schizoid fantasy, borderline state, psychic retreat, projection, splitting, sublimation, reaction formation, intellectualisation, rationalisation, regression, displacement, projective identification, and introjective identification, which last is facilitated by mirror neurones and by echo neurones, which in humans may be memory neurones.

Mental mechanisms enable the avoidance of open conflict, which ontogenetically will have protected family life, and which phylogenetically will have protected life itself.

The ‘unconscious’ is a euphemism for “Me now” until proven otherwise: consciousness varies over time. What matters is the willingness of the perpetrator of an ‘unconscious’ act to take ownership for the act in tranquillity, and to review self-control: marriage makes this willingness less likely.

In unequal relationships, projections can be blocked by portrayal of characterisations opposite to those being attributed. The subjective experience of receiving projections may be penetrative, and so may have sexual connotations.