Doing storm work this past winter and had to drop some ice loaded trees around backlot primaries. We had minimal equipment (two chainsaws, a push pole, a couple of wedges) and an 8-man contract line crew trailing us. I ended up doing all the cutting because the supervisor refuses to pick up a saw anymore and the other person had very little chainsaw experience and didn't feel comfortable dropping trees that close to the lines (even though the power had been killed). I'd dropped about a dozen trees, including a couple of bigger spruce, but was getting increasingly frustrated with the line crew because all eight of them were scurrying around gawking at the trees I was cutting. It was night time, the snow was flying, and there was piles of brush everywhere in the right-of-way, so visibility was already poor and now I had these goofs shining flash lights in my face and standing right where I wanted to fell the tree. I'd already yelled at them a few times to get out of the way and narrowly missed taking the heads off a couple of them with falling trees. Last tree was a big (20+" DBH) Hemlock with heavy snow and ice load and a slight lean back toward a pole. Supervisor thought we should wait and call the other crew to come with ropes. It was late, I was grumpy, and part of me thought I could actually get the tree to go where I wanted. Made my notch, started the back cut....saw pinched, clearly the tree wanted to go the opposite direction. I wasn't abut to let something as silly as physics beat me though; I got the push pole and with three guys on it we managed to open the kerf enough to get a wedge in. Kept cutting until I felt I had a comfortable hinge on it then start pounding wedges and heaving on the push pole. Then "pop", the hinge breaks, tree goes sideways and brings down two spans of primary wires along with the communication lines, thankfully missing the pole by about two feet. I'd already reached my "don't give a fuck point" so I looked at my supervisor and said, "Well, I guess that's all the trees" then turned to the line crew, who all had stunned looks on their faces and told them, "make yourselves useful and clean this up". I think it took them all next day to untangle the mess of limbs and wires and get everything restrung.
Then there was the time I dropped a 30 foot pine top right on to the customers roof. It had a rope in it and we were just going to pull it in to the yard, but I guess the branch weight was more back toward the house so the two groundies couldn't get it to come over by themselves. I was just about to come down and set up a MA system for them when everything went sideways, literally. I guess I'd cut partially thought the hinge and as the guys were rocking it to try and come over the hinge broke. Luckily it only put a half dozen or so holes where limbs popped through. I was very surprised it didn't break any trusses.
First week with a new company I was driving out to a job with the bossman and groundie in the truck with me. We were just casually shooting the shit when I pulled down the customers laneway to drive around back of the house where the tree was. Next thing we know strips of siding and sheathing were being torn from the side of the house. Turns out our pole pruner, which was sticking up in a rack on the dump, caught the clothesline, which was bolted onto the house. Not one of us noticed it was there we were too caught up in talking. It looked like a Three Stooges skit, us jumping out, looking at the house, at the truck, back at the house, at the clothesline, back at the truck, trying to wrap our puny brains around what had just occurred. All the while the homeowner was standing staring at the gaping hole in the side of his house. It was an easy fix, and the customer was very calm and understanding, but I felt pretty foolish the rest of the day.
After dumping chips we forgot to hook the chipper up properly and while driving downtown hit a pothole which popped the chipper off the hitch and sent it under the truck. It broke the bell housing causing tranny fluid to leak all over the road and wedged itself under the axle. Took 2 bottle jacks to get the truck up high enough to drag the chipper out. I can still see the gouges in the road whenever I take that route.
Pulling my rope out after a climb I got it stuck about 100ft up a spruce tree. Rather than go back up and declusterfuck it I thought it would be a better idea to use the chipper winch and when that didn't work I used the chip truck. Honestly, I'm surprised I didn't snap the top of the tree out, but I did have to retire a perfectly good climbing line after that kind of loading.
Clearing brush around a chainlink fence with a saw I knew had a broken chain brake. I have a pretty wicked scar from that kickback.
I slingshot my groundie into a pile of bricks after telling him he should be able to handle the load without the porty.....it was a 6ft chunk of 20" maple...run though a pulley.
When I first started it was common for me to free climb or just use a lanyard.
I won't even get going on the stupid stuff I've done that luckily worked out, but could have gone very very wrong...like trying to hinge swing 80ft leads leaning over houses using nothing more a come along....done that a few times.
The home owners did not like the bran new window that I had installed, so I had to take the old frame in to get new glass put in it. 
Live and learn.
