Why do family recipes never turn out the same whenever I try to make them?

I made chicken and rice the way we did it growing up and i swear i followed the instructions my grandma gave me right. The chicken turned out fine that was just salt,pepper, oregano and lemon juice. The rice i somehow messed up and i don't get it. I rinsed the rice like i was told. Sauteed the onion and garlic and the rice too. I added the right amount of chicken broth and lemon juice but it turned out paste like but crunchy at the same time. I don't get it. Not even the fresh herbs made it better.