One of the annoyances of Thunderbird/Lightning is that the only snooze options for appointments are fixed numbers of minutes - 5, 10, 15, 30, etc - from the time the snooze button is pressed. There is no option to simply 'snooze until 5 minutes before the appointment' - putting the (admittedly small) calculation onus on the software. I regularly am ready and waiting well before my meeting starts, and a '5 min before' option would allow me to fill my extra time with dealing with e-mail, etc. without either a) choosing 'snooze for 10 min', which warns me 9 minutes in advance, or b) calculating the precise number of minutes and entering that in the snooze dialogue. I'd love to be able to just click 'snooze until 5 minutes before' without having so much fuss.