Dissociation is a defense. It is a retreat from reality to protect oneself from an overwhelming threat. It is the freeze from fight, flight or freeze. The experience is then repeated throughout life involuntarily. The experience is one of being victimized by the disorder. Dissociative episode are difficult to shake off and require the intervention by a psychotherapist and/or psychiatrist to control.
Selflessness in the Buddhist sense is an embracing of all that is. Ego is available as a tool, yet it does not sully the experience. Unlike dissociation, it is consciously developed. The experience is one of freedom. You can return to the impermanent, changing self at a moment notice.
Based on the above, I recommend as many experiences of no-self as possible.
©2016 Stephen L. Martin
Painting: Beech Grove I by Gustav Klimt