Prepositions can be a big problem for Czechs when speaking English, mainly because they usually differ in every language. A very common mistake is using the preposition in instead of at when talking about abilities.
It is incorrect to say that you are good in something. The correct way to say it is that you are good at something. This applies regardless of which adjective you use. So we say bad at, terrible at, amazing at, or simply ok at.
For example:
A: Are you good at dancing?
B: No, I am terrible at dancing. But I am good at drinking! Let’s go and get another beer.
