It has occurred to me that bonuses don't suit me well. As a software engineer my ability to work rests upon many different layers of knowledge (my trade), assumptions (there will be electricity at my client's office when I arrive), beliefs (I will get paid).

I work hard to make sure each of these elements are in place, so that I can free my mind of them, and focus on my work.

Well a bonus turns one of my most important factors for employment into a variable, based on my performance. This is a cognitive load that I refuse to bear while carrying out my trade.

If you read up on research regarding bonuses they also seem to lead to worse performance when it comes to cognitive tasks, and I'm unwilling to work with a company that doesn't use data, facts and reason as some of their driving factors.