Some things, like the computer language C, turing machines, lambda calculus, etc. seem to be "naturally" Turing-Complete. That is, they're just Turing-Complete from the bottom up.
On the other hand, cellular automata, many relatively simple Newtonian physics simulations and even Legoes, are also Turing Complete. This seems, somehow, just wrong, yet reductions are so common in TCS, how can we fault the reduction of Lego-brand blocks (and motor) to a Turing Machine by literally building a Turing Machine?
Is there any non-arbitrary way to say when the reduction required of a system is just too weird to consider it "non-ridiculously-Turing-Complete"?