This is a complicated program. The little snippets that appear to show what a tool is used for are great. However, there is often no feedback provided to the user when something is:
1) greyed out / disabled - have a little message appearing explaining why.
2) When you try select an object and drag it and it just doesn't move - have a message that says why it won't move.
There are so many other areas where this could be useful, it would make the more user friendly and much product easier to learn.
In fact, the lack of feedback is pretty much the reason for every one of my posts so far - I know what the Extrude function should do - but have no idea why the profile I want to extrude won't be accepted as a valid selection. There are so many time when a little user feedback in response to a click or drag that yields nothing would be useful.