He said: "I never got the chance to show what I can do. There were times when I was wondering why I had been brought to the club. I'd been bought for a lot of money but wasn't used the way I thought I was going to be.
"I was given 10 games. One I was played left midfield and the majority of the others centre midfield and you'd have to ask Tony Pulis why that was. I just became bemused after a while. When I look back on my career I'll deal with my time at Stoke by saying 'that didn't happen'."
Kitson was one of a number of players who left Reading as soon as they were relegated from the Premier League last season.
He said: "I felt I needed to be in the Premier League and I hold my hands up now and say that was a mistake.
"I was already at a club where I was wanted and my family were happy and I threw all that away for a new challenge because I felt that was what I needed. I was wrong and that was my fault. Nobody forced me to go to Stoke. It was the worst footballing decision I've ever made."