It is our nature to remember the "pain" more than the "gain", its coded in to us so we learn not to be stupid. thus this experience of pain would show up in your experience as doing guild runs over pugs. since pugs may = pain.
however, as Lylirra stated,euwowgold it really depend on what you look for. me having two healing specs mean that my idea of the game for this character is doing instances. so I do a great number of pugs and guild runs.
And I have met quite number of people who are helpful, fun, polite and kind. to the extent that I remember them till now from all those pug runs.
I can not say that this is what you will experience nor this is the way you learn as I did my learning with a guild full of kind and helpful people who brought me to this game back in classic.