My friend in his 20s said to me 'You are old, but useful', and I responded with a gee thanks. At this point he realized I misheard him, and claims he said 'You

My friend in his 20s said to me 'You are old, but useful', and I responded with a gee thanks. At this point he realized I misheard him, and claims he said 'You are old, but youthful'. Anyway, it's now a joke between us and perhaps it is the best we can do: Old, but youthful and by intention or accident - useful.