Is friction something we always want to reduce

In certain things, yes, we want to always try to reduce friction.

In vehicles, equipment, etc. This can help them run more efficiently. 

There are some things that we do and need to use friction for, though:

-lighting a fire. (rubbing two sticks together, lighting a match; all uses friction)

-trying to make your hands warm when rubbing them together.

These are just a few examples. We usually want to reduce friction rather than not, but friction is also very important.

I hope this helps!

The dispersed phase is liquid and dispersed medium in milk is liquid