One of the most common biases is one towards familiarity. This is not a bad bias, but we must be aware of it and how it colours recommendations. This bias can run very deep and affect decision making in ways that we may not understand without investigation. At the highest level, the idea is simply that most anyone is going to favour, possibly unintentionally, solutions and products with which they have familiarity and the stronger that familiarity often the stronger the bias towards those products will be.