There is also a touch of irony. Buffet has always been about rational investment. Nothing explains his approach better, than "Always take advantage of market

There is also a touch of irony. Buffet has always been about rational investment. Nothing explains his approach better, than "Always take advantage of market folly". If you don't know who the mark is, then it is you. Its a good way of making a point, possibly for the last time as he is 83 and will retire or die soon.