My worst redemption was having to spend the 70k UA miles I had earmarked for our 1 year anniversary in Hawaii to visit the in-laws in North Carolina. Delayed 8-hours each way, which made my wife never want to fly UA again. So then we each had 14k useless miles left each (I argued on the phone for 4k miles compensation on the way out, and they ended up putting us on DL on the way back). She ended up donating to her miles to Make-a-Wish. All this instead of a trip to Hawaii.

At least I was able to use 10k UA miles to get two round-trip Island Air tickets that saved us $175, when we finally made it to the Islands. Only used it one way and it was still an effective use of miles. Too bad that's gone now.

My Mom and Sister had to burn all of my Dad's AA miles to get to the UK quick after my Dad's last parent passed away. We didn't have the cash to cover all of us, until my Dad went through Grandad's bank records and found that he had tens of thousands of pounds he had never told anyone about. The whole family then came to celebrate his life.