I tend to get parentheses-happy when I write emails. It’s usually because I’m either writing an exception to something I just wrote (though not always), or because I want to give a specific example to something I just wrote (like this one). It’s habitual. I speak those words in a slightly softer, more British-sounding voice in my head.
At any rate, I find, almost invariably, that you can just remove the damn parentheses and replace it with a comma, like this one. It comes off as a more streamlined thought.