We eat food? You go store? I happy.
Then you start to learn how to form proper sentences, and learn various tenses:
I'm eating food now. She went to the store. I'm happy.
For most people, language learning never goes beyond the point of simple sentence construction. But for Korean especially, there are an incredible number of nuances in sentence endings and conjugational forms, and most foreigners either don't use them or use them incorrectly (myself included). Korean is a very indirect language, like Japanese, so simply stating what you think often makes you come across as rude. As a result, there are tons of ways to form "simple" sentences in Korean, all with different nuances. It's confusing for non-native speakers to know the differences. What follows is the same sentence, just with different verb endings, along with the approximate translations in English. Without further ado, I present, via dialogue, a "Story about Samgyetang" (chicken ginseng soup)!
A: 삼계탕 먹고싶었어? Did you want to eat chicken ginseng soup?
B: 삼계탕 먹고싶었는데. Well, I wanted to eat chicken ginseng soup, but ....
A: 삼계탕 먹고싶었지? You wanted to eat chicken ginseng soup, didn't you?
B: 삼계탕 먹고싶었잖아! You know I wanted to eat chicken ginseng soup!
A: 삼계탕 먹고싶었다고? You said you wanted to eat chicken ginseng soup?
Hopefully this helps illustrate some common verb endings in Korea. Note that some of these actually have additional meanings (especially 는데). Enjoy!