If one or both operands of a comparison have the compile type System.Object or interface type, a reference comparison will be performed. This is often not what is wanted, especially when the runtime type of one of the operands declares operator==.

It should be noted that an exception is made for comparisons to read-only constants - a reference comparison is more likely to be intentional in such cases.

Ensure a reference comparison is really the correct comparison to perform. If it is not then choose a more appropriate comparison. If reference comparison is intended, use ReferenceEquals instead for clarity.

In this example the console will output "False" because a reference comparison is performed instead of using the == operator overloaded in AlwaysEqual.

MSDN: == Operator