This blog is highly personal, makes no attempt at being politically correct, will occasionaly offend your sensibility, and certainly does not represent the opinions of the people I work with or for.
The day I decided I would become a mathematician
I think that the day it became clear that I would become a mathematician was in 1993. I was then 16 years old, the year before the last high school year.

One day the math teacher, said (in French) "Let us consider x a real number". Before he could take his breath for the next sentence, I raised my hand and asked him why he always felt compelled to say that it was a real number. I would have understood that he made the precision had him wanted to choose among, say, the rational numbers, but that the precision was not needed for a real number, because they were all the numbers that were. He looked at me, hesitated one second (second during which, as I understood years later, he might have pondered if he would not be in trouble with Academic Inspection (*) in saying what he was about to say) and replied "because there are numbers outside the set of real numbers".

I was speechless, but I guess that what really stroke me was the complete natural with which he threw that at me, more than the underlying meaning (and the extraordinary consequences) of his sentence. The same thing happened several times during my university studies, every time about deeper and more complex ideas, but it has never been as emotionally strong as this one first time.

(*) A sub-section of the French ministry of Education, made of a bunch of psychopaths who decide what age should kids be told the truth about various things...