Facebook's "On This Day" and "Year In Review" reminders are a great way to look back at the past and remember happy memories. But the operative word there is "happy." Sometimes, Facebook misses the mark — in a big way . Now the company is offering a way to keep sad and unpleasant memories from resurfacing in these nostalgia-inducing reminders. Here's how.Go to the Facebook "On This Day" page here . (You can actually go there anytime, and it shows you posts you've made, photos you've uploaded, and friends you've made on that day. It can be pretty funny.) Then, click on Preferences in the upper right-hand corner. In the menu that pops up, you now have the option to filter out people and dates you don't want to be reminded of.It's a basic and relatively crude solution, but it's better than nothing. Right now, Facebook just isn't smart enough to know that the post from two years ago with 127 likes and 63 comments with a picture of your dog wasn't a happy memory, it was the day your dog got hit by a car and you'd rather not remember that day. But now, you can at least block out posts from surfacing that include your ex.There is something profoundly unnerving, however, about telling Facebook not to resurface memories about a friend or relative who has died. It feels disrespectful, but at the same time, the point is that you — not Facebook — are in control of those memories, and when and how they crop up in your life.