I'm going to judge you for life if you say I seen instead of I saw
Wow, that's harsh. What makes you feel so strongly about incorrect grammar?
The difference between Saying I seen and I saw is the same as the difference between X-ray and x-rayed.
People use grammar based on their environments and upbringing. You should avoid judging others by how they speak. Doing so will demonstrate your lack of understanding when it comes to cultures.
You are not understanding. I want people to learn the proper English grammar.
That's a noble but unnecessary goal. Proper grammar is only a requirement in professional communications. We usually let grammar rules slide in everyday speech.