what will happen if you dont use a sonnet???
Shakespeare will weep for you.
Of course, I'm joking, but let's define what a traditional sonnet looks like:
1. A sonnet has fourteen lines. Depending on the poet, the sonnet could be divided into an octave (eight line) and sestet (six lines) or in the common English structure, three quatrains (four lines each) and a couplet (two lines).
2. The poetic meter (rhythm of stressed and unstressed accents) of a sonnet is iambic pentameter.
So if you had to write a poem, and did not use the sonnet form--what would it be?
Well, beyond the sonnet, other forms of poetry exist like a cinquain, haiku, blank verse, ballad, epic, idyll, limerick.
A sonnet is just a highly structured form of poetry. If you choose to write a poem that does not follow the sonnet's particular set of rules, your poem is still a poem.