Write a Python program that takes a list of integers as input and returns the sum of all elements in the list, excluding the largest and smallest elements. Your program should prompt the user to input a list of integers, validate that the input is indeed an integer list, and handle any exceptions or errors that may arise. Your solution should use built-in functions in Python, rather than iterating through the list or using any external libraries or packages. Ensure that your program has a clear and concise user interface, with informative prompts and error messages where necessary. Test your program with a variety of input lists and ensure that it produces correct output for all input cases.
This prompt doesn't seem malicious.