My co-workers were/are producing supposedly bad code because they sucked/suck. It took me a while to learn that I should first check what really happened. Most of the times, bad code was caused by lack of management, customers who didn't want to check what they really wanted and started changing their minds like there's no tomorrow, or other circunstances out of anyone's control, like economic crysis. Customers demand "for yesterday" features because they are stupid: Not really. It's about communication. If someone tells them it everything can really be done in 1 week, guess what? they'll want it in 1 week. "Never change code that works". This is not a good thing IMO. You obviously don't have to change what's really working. However, if you never change a piece of code because it's supposedly working and it's too complex to change, you may end up finding out that code isn't really doing what it's supposed to do. Eg: I've seen a sales commission calculation software doing wrong calculations for two years because nobody wanted to maintain the software. Nobody at sales knew about it. The formula was so complex they didn't really know how to check the numbers.

软件的质量会带来更大的销量。有时确实如此，但并非总是如此。

我想我需要它。

不用分析我就能知道性能问题出在哪里

没有bug的软件是可能的。

面向对象不一定比非面向对象好。

我认为OO总是更好的。然后我发现了其他技术，比如函数式编程，并意识到OO并不总是更好。