How does marketing impact consumer behaviour?Why might understanding the role of marketing be important to people/you as a consumer?

From an economic point of view, marketing can do one of
two things.

First, it can increase the demand for a good or
service.  It does this by making more people want that good or
service.

Second, it can make the demand for the good more
inelastic.  This means that people will still tend to buy it even when the price goes
up.  Marketing does this by making people think that there is no real substitute for the
good -- that it is in some way unique.

You need to be aware
of this so that you can try to guard against being manipulated into believing that the
product is unique, for example.