How hard is it to write a story?

How hard is writing a story? I mean your own creative unique story not fanfics... I'm really curious... they say its really hard but I mean to ask like as a writer what are the problems you face? (๑•ㅂ•)و✧ how do you think out a unique plot that would interest readers? Do U write formally or informally? How do you even make your story original?

Damn just reading my own questions makes writing seem so complicated already