Performance differences between debug and release builds

Question

I must admit, that usually I haven\'t bothered switching between the Debug and Release configurations in my program, and I have usually opted to go for the

Answer 1

In my experience, the worst thing that has come out of Release mode are the obscure "release bugs". Since the IL (intermediate language) is optimized in Release mode, there exists the possibility of bugs that would not have manifested in Debug mode. There are other SO questions covering this problem: Common reasons for bugs in release version not present in debug mode

This has happened to me once or twice where a simple console app would run perfectly fine in Debug mode, but given the exact same input, would error out in Release mode. These bugs are EXTREMELY difficult to debug (by definition of Release mode, ironically).