Promises make you do odd things.
I promised once that I would always recycle stuff. I have occasionally been too lazy to fulfil this one, but on other occasions I have taken it to extremes, putting the tiniest scraps of newspaper in recycling bins, collecting all the discarded Metros on a train to put in the recycling outside my local station and saving the half of the Sunday lunch that my sister never eats, so I can eat it myself at lunch the next day. Yes, I am very odd like that.
Promises I've made to individual people include: being in bed by 11pm when I was about 15, rather than staying up all night watching soft porn (to my mother), finishing his website by his 60th birthday (to my father), never wilfully hurting myself (to a girl with pink hair), and to add a link to their blog on my blog (it's over there ----->). But there's one more promise that I felt I ought to make, since the person in the question has been so good to me.
So into the studio I went, guitar in hand, plugging in the leads as I went. I opened my mixing program, smoothed the chords to Friday out on the table, struck a chord, paused... and then let all hell break loose.