You don't need to learn the local dialect. Maybe they meant no harm. They laughed only because you were funnier, not because they laughed at you. I think people in the northeast speak with their own jokes, and dialects are the characteristics of every place. There is no need to learn from others just because they have gone abroad. I think the Northeast dialect sounds good.

I study in Heilongjiang University, and I think Northeast dialect is very funny. Students in the south have been assimilated, and I often think some accents are funny, but they are not malicious. So don't think too much. If you want to learn the local dialect, you can learn to speak a few words with your classmates. It doesn't matter if you don't learn. Just be yourself. Now in the university, everyone basically speaks Mandarin, and students come from different places, so these differences are inevitable.