Hidden features - some things you should know

When you're creating WSS 3.0 Features there are some things you should know:
1. features are cool
2. everyting in WSS is based on a feature
3. ... etc. etc.

I can give you many examples why you should use features, when you're are creating a WSS solution.

One thing I noticed last week, was that if you create a feature with the hidden property set to TRUE. It cannot be an activation dependent feature. So when you activate a feature that is dependent on your new secret hidden feature, it won't work.
The strange thing is, that some of the Microsoft produced features are hidden and do have activation dependencies. Very strange.