Nope... Not at all. It can be decompiled back into pretty basic instructions fairly easily with .NET as it basically compiles down to CIL, there's programs out there like .NET Reflector which can easily translate the compiled binary down to IL or even back into a close representation of the .NET code in which it was compiled with. Obfuscation makes it more difficult to decompile it to see that blueprint, but not impossible. Obfuscation is good though as a preventative against decompilation for lazy people who don't feel like deobfuscating your program.
If I wanted, I could get it so that if you opened up my .NET app in a program like reflector, all you'd see is a bunch of junk, perhaps even Chinese characters if I wanted...
