2 years ago I went back to Alaska for a 13-day back country float hunt. I was so excited to go back to the state I grew up in, and be in familiar surroundings.
But I took a sleeping bag that I had picked up at a store in the lower 48, that had a -25° rating, and figured I'd be set. I nearly froze every night, and the coldest it got was about 10° above 0. It really ruined that hunt for me. I'd used the bag many times before, but never in cold temps, and usually half-open and unzipped. When it was over, the first thing I did after flying back to Fairbanks and taking a shower, was go to a real outdoors outfitter and buy a good sleeping bag. I don't want that to ever happen again.