Of course. In my experience, 90%+ of the time when a lab returns unacceptable prints, the problem is in the print-making, not in the negative. (Obviously I'm talking about film processing technical problems like bad color, not out-of-focus prints or other in-camera issues.) I don't normally give a lot of thought to the precise cause in the print-making process when I get back bad prints, but if you don't like the results, you should demand they re-do the prints. If you're in doubt, try to scan the film yourself (or have it scanned by somebody else). If you can get better results with a home film scanner, then clearly the lab screwed up. If not, then it's possible there's something wrong with your negatives (which could be the lab's fault if their C-41 process is out of whack, or your own if your exposure was off or something). In fact, you may be able to spot certain problems (or the lack thereof) just by examining the negatives by eye. For instance, you might see detail that's washed out in your prints.
FWIW, I process my own film now, so I don't often deal with photofinishers, except when I get small prints from scans. Overall I'm happier with my results this way, although it's more time-consuming. I've also produced a few "dud" rolls, mostly when messing with oddball developers or procedures.