For some reason people watch fencing during the Olympics and think "I could do that", and folks with some degree of fighting or combat experience take it a step further and say "I bet I could get a thrust in on that Olympian".
If you know anything about fencing you know they're being ridiculous, since fencers train hard to avoid all attacks and riposte whenever possible, their lightning fast reflexes giving them an edge in battle.
But if you still think it would be easy to best an Olympic fencer in a duel then maybe this BuzzFeed Blue video will change your mind as it shows you why it's not as easy as you think to stab a fencer.
Oh, and being quick certainly helps.