I would like to know what your favorite "security" methods are.

Mine is rotating the data, how about yours?

For simple things, I use RC4 encryption or a variant of it due to its simplicity in implementation.

Can you elaborate on that?

I mean something that is super easy to crack, data^0xFF is a good example.

Lossless compression is another option if size isn't a restriction.

It sounds like what you're actually asking is the best easy, efficient way to obfuscate data, when you don't care how easy it is for an adversary to reverse-engineer your obfuscation and get the plaintext data back again. If that is the case, I'm not sure why you'd want that.

Perfect example, if you want to store data in a configuration file that you don't want an end-user to modify, but you don't want to make it impossible for someone that is more skilled to edit, you can use a known cypher or other weak encryption type. Note, this is now obfuscation and not encryption/security.

Again, modified RC4 can be as simple as XOR all data by 0b10101010, or XOR a passphrase and supply that phrase.

Quite possibly it would be XOR, but a substitution with an XOR is just as cool too! Why the question concerning data security? Anything interesting going on?