I had an amusing incident when I was fixing some bug in a software written in Java. I rather quickly managed to deduce the bug to a portion of a method and I began fixing it. I started by reorganizing the code and after a while I ended up with code somewhat like the following:

     while (true) {
         // ...
 

         for (int i = 0; ...) {
 	    doSomething();
 	    if (someCondition) {
                 updateSomething();
 	        someFlag = true;
                 break;
 	    }
         if (someFlag) {
 	    break;
         }
         if (somethingElse) {
             doSomethingElse();
         }
     }
 

And the damn thing didn't work correctly.

Furthermore, it seemed like the software was caught in an endless loop. It's of course blatantly obvious now, and might have been obvious to you at first glance, that the for loop is missing an ending curly brace. Turns out that the rest of the method was some 10 lines of comments and a closing curly brace. The curly brace was scrolled out of the screen.

It didn't take that long to figure out the problem, but still, it was rather frustrating. The problem was that my brain assumed that the indentation was correct and deduced the control flow from it. The thing is, such problem isn't (in practice) not even possible in Python. Score one for significant indentation.