An especially painful truth in software. Years back I heard a talk by Kent Beck, one of the originators of Test-Driven Development and Extreme Programming. In response to some audience question, he said, "I got into programming because I didn't like dealing with people, and now I'm a @#$&% family therapist for software teams." That comes back to me often.
"The Second Law of Consulting: No matter how it looks at first, it's always a people problem."
- Gerald Weinberg - The Secrets of Consulting