Chapter 14 deserves it's own post, all on it's own; and, I've written about it many times before.
• Who are we to judge the servant of another? We shouldn't.
• There really isn't anything wrong with making days holy or saying they are not.
• Nothing is unclean in and of itself.
• Don't cause your brother/sister to fall; don't do what they think is unholy around them.
• If you think it's wrong, don't do it.