I can't turn off mirroring I've switched to Blender 2.8 a day ago and things are very confusing for me.

Here's what I did: I created a model and applied mirror modifier and then applied it. Then when I started editing vertices in edit mode, the vertices were being edited symmetrically. 
How do I turn off this symmetric editing behavior?
Maybe you have the X Mirror option enabled in the Properties panel > Active Tool > Mesh Options?