Like the brain, memories work by associations.
Memories are related to each other. If you remember a fact in a location, you’re more likely to recall that fact in that location.
This is one of the negative aspects of multitasking and why you should Never Multitask, If you’re doing 3 things you may need to remember all at once, the memories will not be made cleanly.
Memories of special events stick out mostly because they aren’t competing against any (or many) other memories. Memories of routines become genericized. This is why you can’t remember what you had for breakfast yesterday - unless it was something weird.