Re: adrenaline dependency
^ so you're saying I'm not normal ? :(
I totally understand where you're coming from though - that sounds like me a few years ago. I used to be hooked on certifications... and they've certainly helped me in ways I never anticipated while initially pursuing them.
I don't see anything wrong with what you're doing... some people just want to broaden their horizons... my friends call me a polymath, and I'm proud to be one - so Join the club! but also remember that applying what you learn is far more fulfilling than just learning the theory, and obtaining the credentials. So try seeking opportunities where you can apply your newly acquired skills, and this might slow you down or provide an alternative source of informational adrenaline.