I am a brazilian piquet's fan so, maybe I trend to protect him. On the other hand I am very well informed about the whole history.
Piquet was an ancient talkative version of Kimi. He hate midia and marketing and is a very strategic driver (a talent stronger tahn his driving ability - in opposition of one of his rivals: mansell) - thus he needed peace to plan his races. Brazilian press was always stocking him trying to make him a hero, however dislike Fittipaldi he is NOT a gentleman. He is very honest and trustworth, so it is very usual for him to shot answers as: "I made --- while steering". He said that for instance when he hits indianapolis wall. Later when Senna appeared behaving like a hero as the midia would enjoy the pressure over him increased with lot of comparisons. His response was to became even more impolite. Piquet Jr got his father honesty, although he is much more concerned about being kind to press. Most of Piquet's "bad quotes" were politically incorrect jokes with main purpose of bother his rivals and mess-up their concentration. Nevertheless what he said use to be considered by the target. After he suggested Senna to be homosexual the golden boy started to be pictured in companion of girlfriends, Mansell, however, never exchanged his wife

Just to mention his driving qualities: He was a few less talented than Senna, a few less perfect than Prost, a few less tactical than Schummi, a few less strategical than Ross Brown and probably the best ever car developer (driver). Perhaps the current driver closer to his attributes is Alonso (except the trash talking and better in several items).