For some people the idea puts them off trying any form of public speaking and for others who are comfortable with formal presentations often they still find the impromptu element, the unplanned and unrehearsed, extremely daunting.
There is a limited time to prepare a speech and yet a disproportionate chunk of this time gets absorbed in trying to nail down the best speech topic.
This then has a negative knock on effect on writing the speech and the quality of practice achievable given the limited time left.
When you review your short list of finalists there may be one topic that just leaps out at you, you find yourself naturally bonding with it and the speech is beginning to write itself in your mind.
When this happens you have hit the jack pot and the speech writing process can commence.