I have to agree with Sue on one thing, any dream or life situation that is negative we will usually remember. For some reasons the hardships/suffering/trauma also stands out more. Just like the media, the bad news and gossip for some reason gets more reads/comments.
My memory is not good short term, however my long term memory is awesome.
But for me that is irrelevant to dreaming.
I always remember dreams always, I remember dreams from yesterday, or 10 years ago, whether they be positive or negative. I have a pattern to my dreams and the Holy spirit knows and usually sends me dreams/visions I can relate to and if not I look it up.
I had a dream about my dads passing about 10 years before it happened, although at the time I did not know has it related to another future fact that came to truth. Most of my dreams are prophetic, however I give credit to God.
I never forget a dream when I awake or any other time during the day, and never do I have to write them down. I dont rack my brain if I for some reason forgot parts of it as in that case I know its because I am not to know or its of no importance to my situation at that time.
All my dreams are in colour. I have had dreams that have been changed (the future is not written in stone), only Gods dreams I receive do not change. He actually changed the outcome of a few of my dreams.
I also receive many visions that are of happening now.
I once had a dream of watching my self dream the next night and what I was going to dream about, strange but it happened.
So yes it is possible to remember dreams through long term memory.