An inner conflict can get in the way of achieving a dream goal. There are inner conflicts when motivations and/or goals conflict with each other.

Types of Motivations and Goals:
Positive Motivation-A driving force towards some object or condition
Approach Goal-Positive goal towards which behavior is directed
Negative Motivation-A driving force away from some object or condition
Avoidance Goal-Negative goal from which behavior is directed away

Types of Conflicts:
Approach/Approach Conflict-Approach Goal conflicts with Approach Goal
Example:Attempt to summon a friend but summon a different friend
Approach/Avoidance Conflict-Avoidance Goal conflicts with Approach Goal
Example:Attempt to summon a friend but summon a scary monster
Avoidance/Avoidance Conflict-Avoidance Goal conflicts with Avoidance Goal
Example:Try to run away from scary monster but can't move well

If there is no conflict there should be very little that gets in the way of achieving dream goals. There is a positive or negative motivation behind the conflicting approach or avoidance goal, so if this motivation is lowered enough, the conflict should be resolved.

To lower the motivation, it helps to know what the motivation is. If it isn't obvious enough during the dream, perhaps asking the dream would help.

Also, it helps to know that expectations can lead to motivations which can lead to approach/avoidance goals.

Negative Expectation/Motivation:
I won't do it
I can't do it

Positive Expectation/Motivation:
I want to do it
How do I do it
I'll try to do it
I can do it
I will do it

So, knowing your dreaming and can do anything because its all in your mind could be an example of how to resolve an approach/avoidance conflict in order to achieve a dream goal.

I would think that the more self-aware somebody is, the easier it would be for them to identify the conflicting motivations/goals in order to resolve them. However, I'm sure how to gain this self-awareness outside of asking the dream or simply thinking about it.