You can always throw in the 'in order to travel at high speed' option, like traveling at interstate speeds for regular cars, where it's actually somewhat more "fuel efficient" to go at 'cruising speed' (65-70) instead of 'maximum burn' (85-90). So for the important story stuff that happens, like the Grover's Corners launch, people felt it was important enough that they floored it to get there... but most of the time, we all just kinda lope along for the day to day stuff.
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"You know how parents tell you everything's going to fine, but you know they're lying to make you feel better? Everything's going to be fine." - The Doctor
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"You know how parents tell you everything's going to fine, but you know they're lying to make you feel better? Everything's going to be fine." - The Doctor