Minute Errors and Wasted Time

So I just spent the last 2 hours fixing a problem that happened 4 hours of work ago.

While I was editing my map 4 hours ago, Hammer crashed and then a large portion of my map, 6 buildings and 2 walkways and the surroundings, got turned by 1 degree. I didn't realize this happened until 4 hours later, when I saw that one of my larger walls was slightly skewed. I could have gone to a previously saved version, but I would have lost 4 hours of work. I could have copied good stuff from an older version, but I was manipulating too much for these changes to be corrected. So I did the fastest thing and manually rotated each item that was improperly aligned.

It took 2 hours.

It was hard to tell what was wrong because such a large portion of the map was manipulated this way. I went through and had to manually change each item -1 degree, finding all the items was tough, what was even tougher was accidentally turning objects that didn't need to be turned making me have to find those items again and turn them back 1 degree.

Is it really that big of a deal? What is 1 degree? It means my maps would have leaks and would render vis leaves oddly. If an architect had half of the walls in his drawing skewed by 1 degree, the whole thing would be a nightmare and probably couldn't or shouldn't be built. Same thing here, it would just really mess everything up.

It is fixed, but the work was grueling.