When the codebase you are working on has been garbled by 12 years of random tab indent settings and other similar butchery from who-know-how-many programmers (and in some cases totally incompetent consultants) and other nonsense. The indentation in the code (not Python, but C++) is horribly mangled in many places and sometimes all but unreadable, but no one will allow it to be fixed. The other developers I've talked to insist either that it's not a problem, or that we should keep tabs, and if everyone who ever touches the code would simply do everything perfectly and never make a mistake, it wouldn't be a problem.
This is further complicated by a plethora of styles that includes such nonsense as right justifying code, and people who almost literally seem to think the only whitespace you are allowed to use is tabs. Yes, in other words, there are large swaths of code where there are tabs between many of the tokens rather than spaces. Apparently, tabs are not just for indenting for some people.
You would think this would be simple, but in practice, it's not. You would think coding standards and style guides would help, but not if they're ignored, or they were mandated after millions of lines of code was already written in every conceivable style and a few that would leave you gibbering like a Lovecraft character. Then there are the files that had tabs randomly converted to spaces, with indent levels ranging anywhere from 2 to 8, and often at a different indent level than the code with spaces only uses.
As someone who takes code formatting seriously, it drives me crazy, but no one else seems to have a problem with it. I've pleaded to allow the code to be formatted with uncrustify or something similar, but no one likes the idea because apparently I'm also the only person who does any kind of automation and for whom adding an additional step wouldn't affect my work routine. Note: the complaint is not that uncrustify, etc., might break the code, which is a real concern, but that it would be too much trouble to use. This is very incongruous with the fact that these are very good developers who know their stuff and write good code (as opposed to a lot of the people who apparently worked on it in the past.) I'm just surprised how set in their ways people get.
Regarding Python, I thought the whitespace thing was a lousy idea until I tried it. I love it now, but I'm someone who is very OCD about code formatting, so I would format my code in any language the same way that Python requires. It took a little getting used to, but I think it helps make Python code more streamlined to read than C++.