So I was on my friend's server. We weren't noobs at the time, but there was this mysterious thing called chain armor we didn't know how to make. Naturally, we were curious, so we googled how to make it. According to the site we used, we had to set wood on fire by lava to get a fire drop.
Now before I explain what happens, we had this GIANT wooden house with a tree farm on top and a moat made out of water.
Continuing. My friend put several wood blocks OUTSIDE of the moat and poured lava on it. The lava flowed into the the moat, not turning to cobble, and onto our wood house. Said house began to burn. Of course this was WAY before hunger or creative existed. So, fire spread quickly... REALLY QUICKLY. Me, not wanting to have our chests burn and our diamonds wasted (they don't burn apparently), I went in to try and save our stuff. Insert dying messages here.
Then there was the time we didn't know how to grow sugar cane. We traveled far and wide to find it since we didn't think it could be grown. When we finally figured out that you could grow it, we made a giant dirt wall that went on for thousands of blocks and grew sugar cane on top. We dubbed this the 'Great Wall of Sugar Cane'. My friend and I had dug out whole mountains for dirt in order to build this.