You have to be a little careful when using the word patronizing as it has at least three meanings. Firstly it means to act as a patron supporting an individual or a cause. Secondly it can mean being a regular customer of a shop or restaurant for example. Finally it can mean to act in a superior manner, adopting a condescending approach to another individual. It is this last use of the word patronizing which will be considered.
We all have examples from our own lives when we feel we have been patronized by someone. Extensive studies have been made by sociologists of how the elderly are routinely patronized in facilities such as care homes. A common example of patronizing in this context is someone that talks to a younger relative rather than the elderly person because they feel it would not be possible for the elder person to understand. Children often fare no better with adults lavishing praise for the smallest of achievements or simplifying ideas to a level that the child feels demeans them.
Although I am sure the majority of us have suffered at the hand of a patronizing sales assistant or teacher or care worker have we thought through how it makes us feel? Probably our initial feeling is close to anger, why does this person assume I will not understand? Sometimes things can be quickly corrected and a pertinent riposte allows the person to realize that they have prejudged a person and need to adjust their approach. Others, I am sorry to say seem to have no sense of the arrogance of their approach or the signals that someone is trying to send them. In these circumstances there seems to be only two choices for the patronized individual. They can excuse themselves from the conversation and avoid the individual in future. Or, perhaps a little more amusing is to encourage the individual to even greater levels of condescension enjoying the pleasure of watching someone being completely obnoxious without ever realising it.
Finally perhaps we should consider the individual who is patronizing those around them. Do they do it to everyone? Is it age or sex related? Where does it stem from? Some writers have suggested it stems from feelings of insecurity and they aren´t as selfish as they appear, others say that they are just trying to be helpful. Whatever´s the case you will need to find a strategy that works for you.