[exratione]

If we define favorite as most often reached for in reference to present discussions, then probably this. People are persistently surprised by the expected results of cumulative gains in all areas of life, here also:

http://dx.doi.org/10.1371%2Fjournal.pbio.0020187

"Those who get first-generation therapies only just in time will in fact be unlikely to live more than 20–30 years more than their parents, because they will spend many frail years with a short remaining life expectancy (i.e., a high risk of imminent death), whereas those only a little younger will never get that frail and will spend rather few years even in biological middle age. Quantitatively, what this means is that if a 10% per year decline of mortality rates at all ages is achieved and sustained indefinitely, then the first 1000-year-old is probably only 5–10 years younger than the first 150-year-old."