Yes, I know.
Our current idea of Valentine’s Day (or Sweetest Day, or any of the others) is entirely fabricated and supported by the industries that profit from it.
But we can still find value for ourselves in them.
Take me. I know that I can take people for granted, particularly in intimate and personal relationships. I think this is something we are almost hard-wired for. We are primed to notice change, to pay attention to difference. In any personal relationship, difference only lasts so long – and then we run the risk of taking our partner(s) for granted. 
So these little manufactured holidays help me remember.
They help remind me that I need to take time out of my day to tell those I care about that I do, in fact, care about them. They remind me to ask what they really need. They remind me to ask what they really want.
And they challenge me to work to meet those needs and wants.
This system is not perfect. Relying on these holidays should not be the only tool in your toolbox. Remembering to care about the people in your life should be more than a few-days-a-year exercise.
But they are a reminder for me to check up on myself. To really assess if I’m trying to be the best person I can be. That I am working to make my relationships ones where they benefit everyone in them.
They are not a solution in and of themselves.
But they are a start.
 This is far more common for men than women in the West, by the way. For example, the way we treat emotional labor, as recounted in “Stop Calling Women Nags“.