It's not very encouraging that you are trying to overtake someone by speeding.
The reasons other cars want to go fast/exceed the limit is not really something I worry about. What if they're going to the hospital? What if they're undercover cops getting to a scene? What if they just want to get to work fast? I don't care. I care about my safety, so better get out of their way safely. If I notice someone coming up behind me with 120km/hr in a 100km/hr zone, I am 100% speeding up so I can move out of their way. If I don't, all that's going to happen is them having to brake hard, causing other behind them to brake out of instinct... It's the fault of the person speeding of course, but people at fault aren't the only ones getting hurt by their actions.
Kinda like programming.