I went from using a webapp exclusively for email, back to a traditional client. The reason was that the webapp didn't expose enough functionality, and I couldn't change the top-posting default value. Joining several email lists where bottom-posting was the norm, it made sense to adapt to that, and I ended up adopting Thunderbird. Prior to that, I hadn't used a "traditional" email client since pine and Pegasus Mail in the late 90s.