oh man, i mean, i don’t know about or, those are all very different questions, ‘big’ means different things in each of those contexts.
biggest thing i ever fixed was a heavily flood-damaged building, several floors of support, flooring and walls, along with the water damage itself, and all the electronic equipment within. took me about 5 hours.
biggest thing i ever built was this awesome fucking ice sculpture, i wanted to see how high i could get the water to go if i froze it underneath itself while i moved the area of Control Water upward, and the result was a 15″ tall pillar of winding curves and intricate spirals. fucking awesome stuff. i have pictures somewhere. didn’t last terribly long though.
the biggest thing i’ve ever fought, though, has definitely gotta be that sea serpent i scared out of the new york harbor. i definitively won that fight, even if i didn’t kill it, and it certainly hasn’t come back since.