David hired me into his group at DEC in 1985, where we remained colleagues until he moved on. My first visit to the US was a business trip with David to the Boston area. About a week beforehand, as we headed back from lunch, David casually mentioned "got your visa sorted?" - Doh! I headed straight home for my passport - fortunately DEC's travel service could expedite visas. It was sort in a couple of days, otherwise it could have been an embarrassing issue for me at LHR. Memorable and happy times in my career.