How to display detailed error messages into SharePoint page

It happens most of time with everyone when they are working with SharePoint and gets error message is “An unexpected error occurred”, that’s very boring and frustrated error message into SharePoint page, which leaves a number of guesses and questions. 

If you would like to know what exact error description is, then we need to make following changes into our SharePoint web application web.config file. 

1> CallStack=”false” changed to CallStack=”true” 

2> <customErrors mode=”On” /> changed to <customErrors mode=”Off” /> 

Happy debugging :)