I find that yes, a bad sharpen just makes me not want to play anymore because it hinders me from making certain plays. I'm a fairly aggressive skater so i need a sharpen that will bite and bite well, even when cornering hard and leaning at ridiculous angles. For me, a good sharpen is the difference between a really good game and a downright awful game. You can't play well if you don't have confidence in your abilities and a bad sharpen just kills your confidence in your skating.
Often it's not even a case of going to a pro shop for a good sharpen. There are Canadian Tires, Sport Cheks, Sport Marts, etc littered around the GTA that have guys that are mostly terrible at sharpening, but then once in a while you get a total sharpening wizard who really knows what he's doing. Thankfully for me, there two such employees at a local Sport Chek here in Mississauga. I call ahead to make sure one of them is there before i actually go there lol.