Unsolicited advice givers tend to be rigid in the way they approach life in general.
In terms of their thinking style, unsolicited advice givers tend to be cognitively rigid. They typically believe that they are right, and when they approach a problem, they often have difficulty seeing the situation from multiple perspectives. They can be absolutist in their thinking, perceiving things in an all-or-nothing, black-or-white way.
They tend to have a grandiose sense of self or perception of their own competence.
"Great minds discuss ideas. Average minds discuss events. Small minds discuss people." -- Eleanor Roosevelt