I see this as consistent with other replies stating that The is something specific in a group, and A is an indeterminant one of many.
How can this be in your example? When I am saying "I went to the store", I am really saying "There are a group of locations that I could have gone. E.G., the car dealership, the bank, the museum, the store, or the office. I went to the store".
How can this be in your example? When I am saying "I went to the store", I am really saying "There are a group of locations that I could have gone. E.G., the car dealership, the bank, the museum, the store, or the office. I went to the store".