Fantasizing constantly is excessive.
Norm is a published writer and his agent expects him to deliver another novel soon.
Norm wants his next novel to be a great and original idea.
Norm spends some time musing about some ideas then starts putting together an outline he is satisfied with.
Norm spends his weeks day dreaming about different scemarios for his next novel without writing anything down.
Norm is able to compile a novel he is proud of and it becomes his bestseller.
Norm never gets his next novel written because he spends all his time just imagining it and his agent drops him.