You can now hide individual Achievements.
Navigate to Achievements on your profile sidebar and click on an achievement to get started. Once in the detail view, the eye icon will indicate the current visibility of the achievement. Click on the eye icon to hide the achievement. When hidden, they are only visible to you.
You can still opt out of Achievements as a whole in your Profile Settings.
For more information, see Changing the visibility of Achievements. If you have any feedback to help us improve Achievements, be sure to post it in our discussions forum.