representation of interests

Democracy allows us to get our interest expressed and represented.
However between the expression to representation there is a slip between the expression of an interest to its representation in reality.

In a democracy we have politicians represent our interests.
That is the claim, however when we think about how does a politician or a political party try and represent the interests of an entire group of people. Unless of course the group has a common interest, but given our culture backgrounds, our social status, our economic disposition we could have a variegated interest to express and to represent.
How does the politician or a political party represent this diverse interest of its patrons, I am pretty sure there is to be some differences within the same electorate.

Inevitably, our interests and desires clash and politicians are forced to choose between the general interest and the special interest. Most often it is the general interest wins. However while campaigning politicians use special interests to come to power, however once in power they realize that special interest could have an adverse impact on some sections of their electorate.

So politicians are more willing to go with general interests that please the public.

the flip side is they still maintain a self interest and pursue policies that aid their self interest while in contrast only purport an electorate's general interest.