My Cummins is most efficient at 65 MPH...If the posted limit is less than that, I'll drive at that limit and stay in the right lane when I can...If the posted limit is higher, I'll stay on 65 and in the right lane when possible...If I'm passing someone doing less than 65, I stay at 65 with my cruise control on until I'm past and then I move back to the right lane...I really don't care how mad people behind me get; if they're in that big of a hurry they should have left the house sooner...

...Ben
My dad was the same way. He felt he had a constitutional right to stay in the left lane exactly at the speed limit and take miles to pass someone if necessary. In fact he almost saw it as a civic duty to prevent others from speeding and creating a safety hazard.
I thought that was inconsiderate at the time (and I was about 13 at the time). . Seriously...you never know what is going on in someone else’s life. (Probably) well meaning people like you and my dad end up backing traffic up for miles.
Something to consider is that over the years both of you doing that you probably caused someone to miss a few precious minutes with a dying relative, or arriving a few minutes later to comfort a sick child, etc, in situations where there was no advanced notice and no way to “just leave earlier”.
Several years later as an LEO I also came to realize it was not only discourteous, but also unsafe. Folks like you and my dad need to understand that the traffic congestion you create behind you (when you refuse to drive with the traffic flow in whatever lane you are in) has almost certainly killed or injured people. When you force people behind you to slow, as you refuse to get off your cruise control to expedite your pass, it has an accordion effect that leads to chain reaction accidents behind you.
In general we have really poor lane discipline in the US. Some f that is due to impatient people who get frustrated by slower folks staking a claim in the left lane. However a lot of it is caused by fiercely independent (arguably self centered and possibly self righteous - I know my dad was) types like you driving below the normal speed of traffic in the left lane, even if you do eventually go back into the right hand lane.
In short, if you are going to pass, get off the cruise control, get on the gas and and pass expeditiously.
If it takes you more than about 10 seconds to pass a car in the right lane you are passing way too slow and you are putting others at risk.
More to the point, if you are over taking a car at only 1-2 mph and are using the left lane to do it, you should have just slowed 1-2 mph, reset your cruise and *stayed* in the right lane. Or alternatively using your logic: “Oh...you *have* to pass since you can’t go 1-2 mph slower? Maybe you should have just left a little sooner.”