I've been trying to figure this out for an hour.

 I want all my nodes to be "smooth"/aligned not cornered. I have so very many to edit but it keeps changing them back to corners. When I delete one it changes another.

Can I turn this feature off?

Thanks for any help.

With the Node-tool enabled you can change selected nodes at the tools menu bar. 

To keep adjacent smooth go to Preferences->Tools->Node: Disable "Deleting nodes preserves". Sound counter intuitive - but works.