Writing is scary because it eliminates possibilities.
Before writing, there’s an idea in your mind. The idea often looks like a nebulous cloud that consists of words with semantic closeness. The words cluster into a certain shape, but there’s no clear boundary to it. The cloud is still free to move and morph.
You, the author of the thought, feel comfortable in this stage. You can keep entertaining on it, and the words are right there up for grabs. The most attractive quality of the cloud is that there is an infinite possibility of words in it, infinite combinations that can represent the thought, and among them there might be one that can do it the best, at least there are certainly ones that are better than others.
However, when the time comes to write, fear creeps in. Words are specific and have hard edges. Each letter takes up a unique space on the page that leaves no room for ambiguity. The totality of meaning they amount to might be up for interpretation, but the linearity of their sequence is ruthless.
To write is to pin down a particular combination of words from the idea cloud. The problem is that the combination feels somewhat arbitrary. When you first attempt to articulate the idea, some words flow out of you instead of others. But why just these words, in this sequence? And not other, potentially better combinations? The moment you put these words down, the other possibilities dissipate. Something is lost, and you relinquish it.
You look at the sentences you’ve written, you might change a few words, shuffle its order, or flip its structure, but you will always be conditioned by it. Either following it or challenging it, anything new will always be in relation to it, grow out of it, be compared with it. You will be forever damned by the first words you wrote.
The perfection of the yet-to-be-created ideal in your mind has long gone. An infinite probability thought space has been flattened and collapsed into an arbitrary selection of words. Writing is that scary.