Time is money, my friend.
Only if you leave late and have to be somewhere at a certain time. I see that up here in Michigan as well. I like to drive 5 below the posted limit here which is 70. At 65 I get my best fuel mileage and fuel isn't cheap here or anywhere for that matter and it will be going up in cost as well.
You want to go fast, no problem, why I stay in the right lane 99% of the time. I will get in the left lane to pass a slower vehicle, usually a truck and I will kick my speed up to 2 over the limit until I get around that vehicle and then I'm back in the right lane at 65.
Additionally, on the interstate and on unobstructed 2 lane roads, I drive on cruise control all the time. get my best mileage on cruise and my speed stays constant as well.
If I have to be somewhere at a certain time, I always depart with plenty of time to get there. It all has to do with common sense.
'Idiots' and I use that term lightly, fly by me at 10-15 over the limit here all the time and I think to myself..
Glad I'm not paying for your gasoline (or diesel). Besides, at 5 under I don't have to be concerned with getting a speeding ticket either and the roads up here suck, so at 65, I can actually dodge the numerous potholes, which I do. No point in pounding my suspension to an untimely death.
In reality, the only place you have to be is in the ground eventually and driving like a maniac can get you there much quicker.