If someone asks who is the best boxer of all time, the answer you are most likely to hear is Muhammad Ali. The reason for his success, apart from his determination and natural ability, was the fact that he truly believed he was unstoppable and as a result, so did everyone else. Ali once said, "To be a great champion you must believe you are the best. If you're not, pretend you are."
Essentially, if you don't believe you are going to win a race, you probably won't.
This why the best swimmers come across as arrogant, partly because they have earned the right to do so but also because if they didn't behave in such a manner, they'd probably be average.
So yes, be confident, be cocky but don't be a prick. Have faith in yourself and your training but don't feel the need to criticize your opponent. This doesn't show confidence, in fact it shows insecurity. So rather than telling some one else they suck, tell yourself you're the best because at the end of the day, wether people judge you as confident or arrogant is determined by the outcome of the race.
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