An opponent can be necessary to the experience you are trying to prevent them from enjoying.

You need your opponent in order to have the experience you are trying to deny them. Without someone playing seriously against you, the win is empty, which makes the relationship stranger than simple opposition. They are simultaneously the obstacle and the source of the value.

This is worth holding wherever you are set against someone: negotiations, rivalries, arguments. The person on the other side is the reason the thing is worth doing at all. It changes how you treat them, and it usually improves your own performance, since you have an interest in them being at their best rather than diminished.