Non-wireframe edges showing in object mode I created some new edges for my boot mesh, but they show up in object mode when they shouldn't (and none of the other lines do). Why is that? And how do I remove these lines in object mode?

Some context: the lines that show up were lines from a mesh that I joined to the original.
If, after you had just created the new edges, and while they were still selected, you accidentally pressed Shift D, you would have made a copy of those edges, which will show up when in object mode, similar to how they are in your picture.  Try going into Edit mode and select just those edges - go to Edge mode, then right-click on one of the edges with Alt held down, then G (grab) them - if they come away from the rest of the mesh, then they're loose, duplicated edges and you can delete them.