Tectonic events may cause crustal thickening or thinning, metamorphism, magmatic intrusions or any number of other changes to lithospheric density structure. These lateral density contrasts remain long after deformation has concluded, leaving behind lateral gradients in lithostatic pressure. Mother Nature may abhor a vacuum, but any pressure gradient is at best metastable. To oblige her, the wind blows, balloons pop, and perhaps intraplate earthquakes occur. At the sub-continental scale, gravitational potential energy variations are known to cause deformation far from plate boundaries: extension in the Basin and Range or Tibet, for example. Here, I speculatively present three more nuanced examples. The Cheraw Fault, Colorado and the Eastern Tennessee Seismic Zone both overlie Proterozoic suture/shear zones; both feature low-velocity lower crust, negative isostatic residual gravity, and high electrical conductivity; and both display extension perpendicular to their trend that differs from deformation in surrounding areas. Xenoliths from near Cheraw and elsewhere along the same suture document Laramide-aged hydration-induced retrograde metamorphism of garnet in the lower crust and uppermost mantle lithosphere that would have caused density loss of hundreds of kg/m³. Finite-element modeling shows that this excess lower crustal buoyancy promotes uplift but also causes horizontal tension in the overlying seismogenic crust, consistent with the anomalous normal faulting that is observed. I posit that fluids exsolved from the mantle preferentially migrate along trans-lithospheric fracture networks in the suture zones, causing localized lower crustal hydration, density loss, and strain localization. In the New Madrid Seismic Zone, dense mafic lower crustal intrusions related to Cambrian rifting and/or Cretaceous plume activity promote compression in the overlying seismogenic crust, and might explain some of the observed stress rotation and anomalous reverse faulting. Finally, at the kilometer scale, recent gravity imaging of the Little River Fault around the 2020 Mw5.1 Sparta, North Carolina earthquake indicates a material contrast across the fault, likely a natural consequence of recurrent fault slip juxtaposing rock units. However, as the hanging wall comprises low-density rock and the footwall high-density rock, the overburden pressure is comparatively low on the Little River Fault, favoring reactivation under reverse faulting as is observed. These examples suggest that modification of lithospheric density is one mechanism for long-lived tectonic inheritance.