I mean, it’s dangerous, but wrt driving 10mph: the lights are usually synced, so if you’re consistently slow you’re going to run into more red lights where you could’ve made it through by a wide margin if you were going 20. It’s also not just you and another car on the road. It’s going to effect the cars all the way back through the line not to mention the dangerous swerving from everyone else who needs to get to work by 7 or be subject to their boss’s narcissistic tirade.