Why is parallel structure an important part of writing? How could the incorrect use of parallel structure negatively impact
your writing?

For me, a lack of parallel structure means that the writing (the communication/ the message) is "bumpy" instead of smooth. The writing would sound awkward (strange to the ear). And that would make the readability more difficult.  Aim for phrases and clauses that are aligned with a similar structure with respect to nouns, verbs, gerunds, and infinitives..

Explanation:

Ex.

No:  I like to write, to read, and sleeping.

No: I like writing, to sleep, and reading.

Yes: I like to write, to read and to sleep. OR  I like writing, reading, and sleeping.

gregor's attempts to crawl on the walls