To be honest, Thunderbird isn't the most shining e-mail client. First of all, its UI lacks appeal (for example, it doesn't support viewing conversations in a si

To be honest, Thunderbird isn't the most shining e-mail client. First of all, its UI lacks appeal (for example, it doesn't support viewing conversations in a single page, although you can install a plugin for it). And it is sometimes pretty sluggish (probably because it is made with XULRunner, similar to Electron) But I still use Thunderbird despite all these problems. It is the only email client that supports both Windows and Linux, supports HTML, and doesn't require you to create an account and connect to a third-party DB to use it (I'm looking at you, Mailspring!)