Unexpressed negative emotions don’t die… Ever. Instead, they fester.
In a professional relationship between an employer and an employee, frustrations are usually expressed when it’s too late. An exit-interview is interesting, but then, the damage has been done. The insights unearthed during such interviews can be leveraged for other employees, but the actual employee who voiced the issues has passed the point of no return.
Exit-interviews are good, stay-interviews are better. Negative emotions should be intercepted quickly, so they can be expressed, preventing a nasty festering wound from manifesting itself. Consider implementing frequent and recurring stay-interviews.