I’m currently writing a paper on Catullus and I arrived at a grammatical impasse. It led me to look this up:

Statements in parentheses ( ) can be ignored when it comes to Subject-Verb agreement.

Thus, I didn’t have to completely rework a handful of sentences to avoid the awkwardness of a possible subject-verb disagreement. Trust me, this revelation is profound considering how often I use parentheses.

(source)