PhilK:
I find it irritating and lazy. Even more so when it's the wrong letter that's stretched:
Yes! It's bad enough when used repeatedly, but when it's the wrong letter being drawn out that's even worse!

And I agree that it's generally bad form to emphasize dialogue like that, as well as include endless SMACK's and OW's.
I actually find it interesting to read older works by some established authors here and then compare those to their more efficient use of dialogue and description as they have matured as writers (not mentioning any names!) I know that personally, my earlier stories are certainly not as 'lean' in dialogue as my later ones.