Conflict can occur between control actions from one system and unintended side effects of otherwise unrelated control by another system. It may be easier to see this if we go a bit far afield from interpersonal conflict.
For example, microbes in the rumen or first stomach of ruminants like sheep metabolize hydrogen produced by other organisms, producing methane. The sheep burp methane. This methane constitutes more than 40% of the greenhouse gases produced by New Zealand. Being close to a large hole in the ozone layer, folks in New Zealand are very interested in reducing greenhouse gas emissions.
http://www.wired.com/news/technology/0%2C1282%2C39654%2C00.html?tw=wn20001030
Investigators have reared and kept sheep lacking methane-producing organisms, so they know they're not essential. 5% of sheep in the field produce 40% less methane than other sheep, and they don't yet know why. Since the methane production