I'm fascinated with what can be done with electronics!
I've been professionally engaged with hardware and software design for real-time embedded devices since 1976, and I haven't lost any of the fascination. As a hobby, it is a bit more challenging in these modern times. Look at the complexity of the mbed module itself which is generally not producible by most on a hobby basis. But leveraging designs like the mbed enable the kind of hobby development and rapid prototyping that makes it possible to create solutions in the home laboratory.