"Sorry for the delay, I was on an 11.4 hour trip to Tesco."
Sorry to hear that, your Tesco obviously has till queues the same length as my local store, which is why I now shop at Asda.
Perhaps it's just because I'm still a low hours PPL, but I do use the whiz wheel in my flight planning. However I recall spending many stressful hours learning 103 different calculations I could do with the thing...and now use approximately two and a half every time I fly (and suspect I have already forgotten most of the remaining 100.5). Seems I'm not the only one who either does mental calculations or uses a cheap Casio...