As a paranormal investigator, a poltergeist is any haunting that shows a level of cognizance. In short, any spirit that can interact in our world and shows some degree of self-awareness is considered a poltergeist. Consider an EVP session, if the spirit you are attempting to communicate with chooses to answers your questions with the appropriate responses in real time, this interaction shows that the spirit has a level of self-awareness. By my definition, any ghost that can participate in spirit communication, move psychical objects, react to current events, and exhibit the ability to choose is a poltergeist. When you experience this kind of haunting, the only question is how classify the poltergeist by the level of activity experienced.
There are some hauntings classified by the paranormal community has “routine.” The common definition for a routine haunting is a spirit that repeats the same behavior over and over again as if it has been recorded and played back repeatedly. I do not believe in this definition. In my experience, I have never witnessed a haunting where the events were repeated exactly the same. I have witnessed a haunting where the events were similar, but there was always some variation. My definition of a “routine” haunting is one where the spirit is not aware of our existence; we may be witness the spirit, but it doesn't have the ability interact in our physical dimension. It may be self-aware, but it is not aware of us. This unawareness of our prescience could give it an appearance of being repetitive.
Ghosts are very rarely evil or malevolent; most spirits tend to be harmless. The expectation of evil is usually caused by one’s fear of the unknown, and what they have seen in the movies. The soul is the essence of a person. So the same personality traits they exhibited when they were alive, will most likely be exhibited when they are dead. The only question is during an investigation is, does the ghost have the ability to interact with us?