Fate is not, as it is often thought to be, chance or destiny. Destiny would seem to imply inherited traits. Fate is planned, chosen - even if we are unaware of the choices and plans we make.
Fate is not written in stone. People change a little each day. Their decision-making process often changes with them so in turn their fate changes.
Because fate is a thread that ties everything in life together, the Ancient Greeks described Fate as three weavers: one who spun the thread of life, one who wove it into a pattern and one who cut the thread short. Their Fates determined each human life span, whom that person would know and what they would do. And not only did the Greek Fates hold this power over mortals, they had it over the immortals as well. The Greek Gods themselves bowed to the power of the Fates.
Their fate was a belief, the philosophy that everything is here for a reason - whether or not the reason was known. Should the reason for a certain fate be discovered either great rejoicing or intense tragedy would follow - this is why some thought of fate as Truth.
No two people have ever lived the exact same life - as far as I know. But in the past, changes occurred less often and on a more local scale. The generation gaps of those times are not comparable to the generation gaps we see around us now. And as change gains ever more momentum, as the gaps grow, fate becomes something each person must find for themselves.
It is a given that while a person can become good at many things, it's pretty much impossible for a person to know everything. There is so much information out there, society can't keep up with itself.
The choices each person makes when they decide what they like and dislike, what's their favorite and what's their fear - these choices narrow down what a person will want to know about, what they will want to do. It's part of why each person behaves, thinks and feels in their own ways.