Newcastle won 3-0 on Wednesday night through goals from Yoane Wissa, Anthony Gordon and Harvey Barnes.
Bosz said afterwards: "In some areas (I wasn't happy), but in others, I think we did well. That may sound strange. Most importantly, though, we were unable to make any kind of impact or create any chances, which is what football is all about.
"I have to say that we gave away our goals very easily. In between that, I think we did an excellent job. We were able to maintain possession and build up from the back, but we didn't really threaten.
"When you give away goals like that, it's more than frustrating."
Meanwhile, PSV defender Jerdy Schouten also said: "It's a disappointing night for us. They pressed us high, but I don't think that was the reason why we lost tonight.
"We just weren't good enough on the ball. I don't want to blame injuries or anything else, we just weren't good enough."