I do only partially qualify since I only lost-and-regained my passion for (software) problem solving after an early burnout, not because of an expansion of perspective.

What fuels my passion: I try to stick to languages and concepts that are puristic. I loved SmallTalk, which is pure OO (so much more than Java). I love Haskell, which encapsulates a particular style of functional programming quite well. I love LISP, since it represents and embraces metaprogramming quite well. The more a language deviates from these extremes, the less 'thrill' I feel using them. I always try to solve problem with the purest form a paradigm has to offer.

In the real world, I am able and perfectly happy to choose whatever tool fits the need best and adapt to the team. But I will certainly voice my opinions ("This is a planning task - let's not reinvent the wheel - and waste time and fix unnecessary bugs - and just send the data to Prolog and translate the solution back into our program") tho and what I do in my free time is not bounded my industrial needs.

Every paradigm offers a different perspective on programming and is worth exploring. Thankfully I am not genious enough to run out of this particular motivation in my lifetime.