Some good software
Nothing particularly insightful in this writing, I just feel like writing about software I particuarly like. In particular, what I mainly like in a piece of software is that it does its job simply and effectively with no bugs. This is surprisingly rare.
Anki
This program is already fairly well known, so I won't spent too much time talking about it, but I've always been very pleasantly surprised by how well Anki works. I've never had a moment where I feel like I'm fighting against it to get it to work how I want it to, which is very impressive for a complicated GUI application that involves syncing states to a server that I have used daily for over 2 years.
Claws Mail
This one I only learned about just a few months ago, but I love it. For a long time I was using Thunderbird as my email client of choice, but it always felt a bit bloated and there were many UI decisions I didn't like (I really do not want emails I open to be in a new tab). I also strongly prefer writing and viewing my emails in plaintext, and while this is possible on Thunderbird it really does not feel like the intended experience either way. I also didn't like that by default it had system notifications for every single email you get.
I was thus extremely happy to find out about Claws Mail, which solves basically every problem I had with Thunderbird and works without any issues. It even automatically wraps your email to the 72 character standard when writing in plaintext, an extremely useful feature that has made me even use it for purposes it wasn't intended for, such as writing drafts of plaintext documents. I know Vim can do this too, but being able to do it without configuration is as nice as it is rare. It even has an RSS reader plugin, which I am using for my RSS needs.
That being said, I don't think this mail client is for everyone. You are forced to view and write plaintext, HTML emails are not an option at all. I think HTML email was a mistake so this does not bother me, but may be an issue for some. The other issue is that Gmail addresses are miserable to set up for Claws Mail, but this isn't the client's fault but rather Google's for massively overcomplicating the process of using third-party clients (Except for Thunderbird, which has dedicated measures for setting them up). I wanted to switch the one Gmail address I had off Gmail anyway, so this ended up just being encouragement to finally switch off Gmail. (If you're curious, I now use Migadu for my email hosting. I strongly recommend it, very good feature set for only $19/year)
Exact Audio Copy
This one's a bit of a pain to set up compared to the previous two, but once it is set up it, again, just works. Software with a pure Win32 UI in general always feels reassurringly stable to me, likely because it suggests that the software is at minimum 20 years old but still worth using.
foobar2000
Probably the piece of software I miss most whever I happen to be running something that isn't Windows. Like Exact Audio Copy, it's a no-nonsense Win32 UI application that does what I want it to do with no issue. Extremely customizable as well, and very intuitive to do so. No configuration files needed, just enter the UI editing mode and start visually adding new layouts and screens. This can be a dreadful process in other applications, but foobar2k manages to do this perfectly from personal experience.
(I will say that this praise all only extends to the Windows version. I have used the mobile version of foobar2k before and, while adequate, I remember not thinking it was anything special).
ArrowVortex
Specifically, the original (legacy) version before it was open sourced. While there are a few small bugs, and it lacks a few features I would like, it is by far the best chart editor I have used for any rhythm game. Extremely stable and intuitive, and most impressively has its own custom UI not based on any framework. It also innovated some extremely impressive features, such as reliable automatic syncing of single-BPM music. I wasn't surprised when I learned the original creator of this piece of software had professional experience making level editors for AAA games, nor that the aforementioned syncing feature was part of his master's thesis at university.
Everything
I couldn't believe this application when I discovered it. I figured that considering how slow and unreliable Windows' built-in search was that it was an impossibility to make it good. Everything demonstrated that not only is it possible, but it's even better than anything I have heard of for other operating systems. Search results are displayed instantly and intuitively, and detailed searches can be made trivially. I have only encountered a bug once, and it was simply fixed by re-indexing the drive, which only took a few minutes at most despite being millions of files.
For further investigation
What do all of these pieces of software have in common? Whatever it is, is it the source of the quality of the software? This question is mainly meant for you to consider for yourself, but I'll write my own surface-level attempt below.
The programming language choice is fairly diverse; Anki is written in Rust, Claws Mail in C, Exact Audio Copy in Modula-2(!), and foobar2k and ArrowVortex in C++. It's unknown what language Everything uses, but considering it's a low-level Windows utility I would guess C++. The UI toolkits of choice are Qt (Anki), GTK3 (Claws Mail), and Win32 (EAC, FB2k). Besides ArrowVortex (2016), all of these programs are very old too; Anki being the newest at only almost 20 years old, with EAC being the oldest with its first release in 1998. None of these are CLI/TUI applications either. Interestingly, more of these are closed source than not. None of them are for profit.
Considering the above observations, I believe the simplest explanation is that these are pieces of software made by experts in their field over the span of decades with reliable, low-dependency languages, and a goal of producing the best piece of software possible rather than the most profitable. I hope that someday I can make something as good as these programs.