I don't know that I can give you any, but I am also firmly against mother's/father's day. It's not only an issue of building the pride of people, but also an obligation. Whatever is done for a parent on these particular days could be done any other day of the year. Why is it that people only choose to do for others on one particular day? In addition to that, how can you give in love when you're pressured into fear if you don't give?
The bottom line is that this is still observing days, as the pagans would do. I've only done research into the mother's/father's day very briefly, and nothing I was finding sounded satisfactory, and I was getting mixed answers depending on who was writing. Usually, when I see the mixed answers, or a standard that's repeated off of one website (like wikipedia) there's usually something pagan behind it, even if I can't see it yet.
No matter what topic we want to discuss, here's the bottom line: Show me anywhere in Scripture where these days are recognized or observed by the Christian church. If we can't find any Scripture for that, then there's something else going on behind why people are doing this by tradition today.