As a self professed script writer and novelist I have an opinion . . .
The beginning is so important. One has to engage the audience/reader very quickly. This demands ones creativity need to be unique, challenging, and interesting.
I am currently writing a novel and it is a concern that my beginning is going to be worthy of the ending, and visa versa. That is, I believe that the end must be gripping as well.
It is like drinking something to see if you like it . It may taste good at first, and the aftertaste should leave the sampler satisfied.
Sure, one wants the audience and readers to watch and read until the end. I suggest that one really consider how it will end so that the reader is satisfied with the time and effort they took to read or see the piece.
In my opinion- one needs to make the end a great one! Really consider a variety of endings and choose one well. You will make an admiring reader and audience, and who knows- you might set yourself up for a sequel or start of another trilogy . . . . Make it a great ending from the beginning.