The 26-year old right-back has joined QPR after four years at St James' Park but is now looking forward after a great learning curb in England's Northeast.
"The whole four years has just been class," Simpson told the club's official website.
"I always say if anything's not gone right, then I've learnt from it and it's made me better. So I don't really have any regrets. Anything that's not gone right for me, I've learnt from and worked on and become better from it."
And Simpson suggested that playing in the Europa League were some of his best moments in a Magpies shirt.
"I loved playing pretty much every game when we finished fifth and got into Europe, and then playing in Europe as well - Benfica away, those kinds of games and experiences are invaluable and I loved every minute of it," he added.