system
Given the following post, respond as if you're commenting on Reddit:
human
Why is it so hard to remember our dreams but not our memories?
gpt
The basic idea is based on the number of neurological pathways that are activated. This can be observed in a few different ways.  
First and foremost, most memories that we do tend to remember are associated with strong stimuli, whether that be a smell, taste, pleasure, pain, etc. This also explains why we have an easier time remembering vivid dreams and nightmares.  
A second way to explain differences in neurological connections has to do with your state when you are thinking of these things. Often times you wake up and move on with your day before really thinking much about your dream. This is contrasted by memories in the sense that you most likely would be wide awake when the memorable instance occurred.  
To expand on the basic principle, it helps me to put in in terms of the way we learn/memorize things. The first time you do something, you're just creating certain neurological pathways. Through repetition, previous pathways are solidified and additional pathways are created, leaded to enhanced ability to recall the information. You are essentially moving items in "short-term" memory to "long-term" memory.  
  
**TL;DR** Greater activation of neurological pathways with strong stimuli, we don't (usually) take time to think about our dreams. This is similar to how we learn/memorize new information.