People need to believe in themselves to achieve big dreams. What good is attempting HSC if clogged in the back of your mind, is someone telling you that 'You will never be able to get 99.95 ATAR'?
So this is why, even when there's almost no possibility to succeed and you think it's the end of the world because you didn't devote enough time for study or the like, you should still look positively and give it all you have. Great people in life, such as Nelson Mandela along with Albert Einstein didn't just learn how to succeed. They also learnt how to fail which in my opinion, is more important. Because only by failing, do we learn how to correct ourselves.