Thunderbird would be a great email client if it natively incorporated the snooze and send later options into its interface, rather than through third-party vendors. The extensions for both features or tools are horrible and have nothing to do with Thunderbird's graphic design. I love Thunderbird, but the only thing that keeps me from making the final jump is that these options aren't native to the email client, which makes me feel like an incomplete and frustrating experience when I have to use third-party functions. Only in this way can Thunderbird surpass Outlook and any other email client. I hope this becomes a reality soon. Best regards.