I'm a piper and have heard some really awful pipers in my day.
A couple of things could be at fault for sounding awful
1. They are self taught almost everyone that says they are self taught are bad
2. The reeds in his/her pipe have been played past their prime which causes nasty eye shattering squeals and squeaks.
3. They're pipebag needs to be seasoned. If you don't season the bag the air leaks out and you can harly play at all.
I think every piper has some sort of dilemma every once in a while that they can't control.
I.E. I played for a funeral today it was about 19 degrees and the wind was blowing like crazy while i was playing I had a choke on the chanter .
I don't know what non pipers think but some might say tats awful most pipers if they heard it would know it was because of the cold.