Necklines—I curse you!

I'm frustrated. Really frustrated.

After reading and watching numerous tutorials and spending ridiculous amount of hours slaving away on my sewing machine, I still cannot get my necklines to lay flat. I'm doing something wrong, obviously, but I'm at a loss on where I've gone wrong. This ONE thing has taken all the fun out of sewing and it makes me want to punch a baby. I know—it's ridiculous. Sewing necklines has successfully transformed me into a heartless baby-punching dirtbag. Please, take the babies away from me before I smoosh their faces with my bony fist and curse their perfectly-made bibs with necklines that do lay flat!