I would much rather have someone on my team who ships less but whose work I can trust than someone much faster whose changes leave me wondering what problems we’re going to discover later.

And when production breaks (and it will), I need the person who made the change to actually understand it well enough to help fix it, instead of showing up with no idea what is going on.

You can obviously be an asshole about how you do it but I don’t think pushing back makes someone toxic.

You need to be flexible and compromise when the business trade-off makes sense. But you also need a backbone. If you think something is going to cause real problems, bringing it up is part of the job.