How am I ment to understand cards?

I have been playing yugioh for a bit over a year now and have started to get decent.

But one issue I have is trying to understand what my opponents deck does. For example when I see a white forest card I just die a bit on the inside and it makes it very hard to learn.

Some decks I can grasp just fine but some make me feel empty and sad.

How can I deal with this dread I get against certain decks?