How easy is it to s&%^ in Kernel

I am a unix user and application developer with reasonable experience in developing server applications on unix (solaris, hp and linux) systems. However, I have never felt in control in terms of knowing "the internals" as most of my experience has been limited to making system calls at best and writing wrappers around that to handle difficult situations. Now, I want to know Linux better because I see it (or a variation of it) as the future like most of you do.

My question is: How do I know it well enough to dream in it? I know it is a stupid question but you get the point.