I don’t see the possibility of a painless selective memory loss anytime soon but still love the idea of it. I came across the idea in the movie “Eternal Sunshine of the Spotless Mind”. In the movie, the doctor first creates a map of memories in the brain related to the event the subject wants to forget and then somehow deletes these memories.
Meanwhile, science is still trying to figure out the cell or the molecule (chemical) responsible for the memory. But as Lyall Watson said, "If the brain were so simple we could understand it, we would be so simple we couldn't “. Common knowledge is that memory is stored in neurons and the synapses they form in the brain. But it’s not clear how exactly. Although electrical stimulation of a certain neurons triggers a memory like that of a smell or a sound or a scene from the past but destroying those particular cells does not lead to the loss of that memory.
Nevertheless, scientists were successful at deleting certain traumatic memories in rats’ brains using a drug which causes amnesia. Interestingly, the drug obliterated only traumatic memories. Though it is not clear how it happens, it could have some really good uses. It can be a wonderful gift for certain people like victims of childhood trauma etc.. People can start over without their past lingering over their heads.
I believe hypnosis could help in selective memory deletion but it’s just a guess. I've heard "Time Line" Therapy has a method for 'blocking-out' memories. But mainstream research in hypnosis is lacking.
Like many far-fetched ideas, this one seems like fiction.But as Isaac Asimov put it, “Science fiction writers foresee the inevitable”. I just might get the procedure done in a few years.