One of the most poisonous words in the English language is "Impossible." It's often added to phrases that are uttered too often. You can't do that. You'll never make it. That's a stupid idea. You are not good enough. Don't be a fool.
I love those stories where the boundaries of impossible are defied. Where the target of such criticisms stand up and say, "Oh yeah? Watch me." That's what these kids from Thailand said when they were told that they couldn't be soccer players. Do yourself a favor and take five minutes to watch this.
What have you been told is impossible?