For some strange reason, some ESL instructors think they can improve any activity by making it as some kind of competition between students or between groups. Unfortunately, doing this can be counterproductive and actually discourage the most serious students.
To illustrate, consider an information-gap activity like the one from the March 1st posting Another Conversation Activity: Listen to Partner and Ask Questions to Complete Information-Gap Chart . In this, pairs of students fill in missing information in a schedule by talking, asking questions, and using clarification strategies.
Imagine the teacher tells the students that he will give a prize to the pair who finishes the schedule first. This is what will happen and how students will miss out on the skills that the activity is meant to develop.