Used to describe a bland uneventful person. Much like the flavor of ice cream this person lacks excitement, but in their life. Usual causes include; holding a stable job, having children and being involved, having good mental health, having stable relationships. This state of being, frankly, lacks flavor.
After I told my brother in-law that the only thing he had ever given his children is diabetes he called me a vanilla ice cream cone.
even my goodness as a person was questioned (total bullshit)- basically a message that was completely baseless and formed in some dark corner of his imagination...