An anniversary day is not inherently important. What is, is either the memory of the importance of that day, which can be realized at any moment of any day, or, the importance of the person with whom that long ago occasion had any meaning, which may mean you are continually grateful for someone in your life and need no “special day” to make that person important, again.......................................And you tell your spouse that every year , right??
Actually, I’ve told my wife this, and she generally agrees. We do eat out or do something around our anniversary, but make no pains to do something a any specific day for that or birthdays.