Okay, there are three other common scenarios where I have observed pairing to be immensely valuable:
1. You are in the middle of a death march and pairing with a team mate gives both of you the moral fortitude to keep going (and keep your programs relatively correct and relatively secure).
2. You are working on a tedious but difficult task and working with a team mate makes it so that you are less likely to make mistakes despite the tedium (as well as gives you the moral fortitude to continue with the task).
3. You are working on a difficult problem and you have a team mate that you can truly collaborate with to find solutions neither of you would have found on your own. (The Jeff Dean + Sanjay Ghemawat collaboration at Google is the most famous example of this.)
In any of these cases, it is important to pair with someone compatible with you. And you can build compatibility over time.