4. Students "hijack lesson" - The lesson doesn't go where you want it to
When teaching English as a foreign language, you can always count on students hijacking a lesson. To some extent, this can be a good thing. It shows that students interest, and as long as they are participating and conversing in English, it is a productive experience. However, if the lesson strays too far off topic, in a direction you don't want it to go, it's important to correct the problem by diverting the conversation.