midas Well, you know what they say, there's no limit to perfection.
I don't think being obsessed with proofreading is a bad quality, on the contrary, your clients will always appreciate that. Just be mindful of the time you spend on it. Perhaps using a productivity app like Toggl could help you be more aware of how much time you spend and manage it a bit more carefully?
In any case, I think all translators have a bit of OCD when it comes to our work and that's not a bad thing. Just make sure your clients also aware that you're doing several rounds of proofreading.