Addiction can take many forms, sometimes it isn't a simple matter of habit but can be a deeper psychological need. Smoking especially can be seen as an emotional crutch ("I need a smoke to calm my nerves") but it's all a part of the same need to for us to occupy our time and maybe forget things that trouble or distract us. Sometimes even the keenest mind will forget logic and seek a way, sometimes potentially destructive, to occupy it or find some peace.

#thealliance