On rare occasions. But typically, if my pipes are cleaned well, my charring light proper, and my cadence slow, then I'll get a good smoke. Every now and then my taste buds and/or sinuses will act up and throw off the enjoyment of my smoking, but that's rare.
Unless I'm smoking a shitty tobacco. But the solution for that is obvious.
edit: For those smoking outside, one other factor people forget to consider is humidity. A muggy summer's day can make for a poor smoke, as can a wet and windy day. If you're smoking outdoors, be mindful of your surroundings and prepare accordingly. For example, if I want to smoke outside and it is muggy as hell, I will get a proper char done indoors or under some cover first before venturing out, and I will also be judicious in what tobacco I choose to smoke. For me, muggy weather calls for an easy-going VaPer or aromatic. Cold and wet weather calls for a solid english or burley w/ DFK. Windy weather calls for me to get my ass back inside.