Karsdorp has joined Feyenoord on a season-long loan.
“You're left alone there for so much of it," Karsdorp told Voetbal International.
“Some lads walk in five minutes before the start of the training session, while others have already been in the gym for two hours. You can not speak to anyone through an entire training session, as everyone does their own thing.
“When I got to Roma, I was really shocked. Was this the atmosphere in an Italian dressing room? I much prefer the approach in Holland, you have more of a laugh.
“I never had faith in myself at Roma. When I left, it was like taking a weight off my shoulders, all the tension disappeared when I found out that I could go."