Can Perception of a Situation be Controlled by Ones Self?

Our perception of a situation can be controlled by no one but ourselves...

...we choose our perceptions, either consciously or unconsciously... but they are our own choice...

We can always change our perception. This is what the whole "is the glass half-full or is the glass half-empty?" question addresses.

At any point, we can choose how to look at a stituation which in turn determines our attitude (and most likely our actions). If we focus on negatives, we see a negative situation. If we focus on positives -- we will see a more positive situation. All of that is perception.

In addition, different people may have a completely different perception of the exact same situation. (Many Holly movies/TV shows have been based on this premise) due to bias, training, attitude, etc. This is just human nature. So two different people can sincerely believe themselves right about something yet believe the other is completely wrong. And yet each may be arguing largely from "perspective" or "perception" rather than from fact.

A lot of times,sometimes, no.

How else would it be controlled?

With a lot of self reflection and over analyzation...yes, its possible

Yes this is possible. When we are confronted with a situation that affects us in a major way we can take time to think about why we react to it so strongly.

Negative perceptions usually stem from feelings of fear or hurt or anger. Where are these feelings coming from? Past experiences? Loss of what we thought the situation really was? Having hopes and wishes ignored by another person?

Sometimes writing down feelings helps. What good came out of the situation? What bad come out of it? What was learned? Learning more about how and why we react to something is a positive for it helps us go on with a sense of empowerment.