I suffer from the disease of writing books and being ashamed of them when they are finished.

[J’ai la maladie de faire des livres et d’en être honteux quand je les ai faits.]

Charles-Lewis de Secondat, Baron de Montesquieu (1689-1755) French political philosopher

Pensées Diverses [Assorted Thoughts], # 83 / 837 (1720-1755)
    (Source)

(Source (French)). Other translations:

It is a kind of sickness with me to compose books and to be ashamed of them afterwards.
[ed. Guterman (1963)]

I have the disease of writing books and being ashamed of them when I have written them.
[tr. Clark (2012)]