Best experience: Discovering miles! It's been life-changing. It's been challenging to learn the rudiments of the good/better/best/worst redemptions, and the challenge is just getting tougher as our miles earning opportunities tighten up.
Worst Experience: Realizing that I've just made a boo boo right after I book a ticket. I recently booked an award for the wrong day, because I didn't correct the search engine. A moment after I hit submit, the realization gob smacked me. It took an hour on the phone to correct it.