The quality, or lack of it, in labs varies.
Long before digital photography, I took some medium format negatives to one highly acclaimed lab close-in in the Portland metro area to get 11x14 prints - what I got were prints with an insane magenta cast. I went to a second lab that caters mostly to professionals - I got prints that were reversed (they loaded the negatives with the emulsion facing the wrong way).
Now when I find a good lab for color work, I stay with them.
"Great photography is about the visual effect upon the viewer, not sharpness." - Stephen Gandy, Cameraquest