Few stocks ever land in the "buy now and hold forever" category for me. I can come up with a bear case for nearly every investment I have. However, there are a few companies that have such a rock-solid investment thesis that I doubt the worst-case scenario would ever materialize. These stocks end up in my "buy now and hold forever" pile, and I've got two that I think fit in this category.Amazon (AMZN -1.93%) and Taiwan Semiconductor Manufacturing (TSM -0.54%) are two companies in this rarified section of my ...