This story gets me going.

Mrs Dulcamara does not have the same last name as I do. In the 25+ years we've been married, only UA has made this at all difficult. I once tried to upgrade her to F on a transcon. The UA rep at SFO accused her of stealing my MP number and downgraded her to a middle seat in Y. UA's response to my complaint was an HK49 for her and a "It's the way our system works." for me.

AA, on the other hand, makes this easy and pleasant.