To me, I see pushing rules boundaries as part and parcel with exploring fantastical worlds. Elves, dwarves, and dragons exist. Those aren't "real". Magic spells that allow you to fly and shoot fire from your finger-tips also exist but also aren't "real". If we're already breaking biology and meta-physics, why assume basic physics works exactly the same way either? For some, I think it is re-capturing the child-like attitude of wonder, excitement, adventure, and asking the question "what if?". This, of course, may be tempered by campaign tone; something that might happen in a DnD campaign but likely not in Call of Cthulu, Kids on Bikes, Monster of the Week, etc