$1-$ why does making choice get harder when you have more options $?$

$2-$ why does Netflix use two approaches recommendation $,$ a technical approach and a social approach $?$

$3-$How do the technical recommendations work?

$4-$why it is important for Netflix to be able to make appropriate recommendations for their user?

$5-$why the content of Netflix is different from one country to another and how Netflix softwear sloves this problem $?$