Q: Hmmm is there any particular reason why some people use Cb to refer to B or E# to refer to F? Coz I've seen this in a couple places (mainly Synthesia)
A: it's not some people, it's some situations. if you are in the key of Gb, there is the B note but if you call it B then you have Gb, Ab, Bb, B, Db, Eb. this gets real messy if you try to put it on the staff. to use a key signature on a staff you just flat everything you need and then play the scale, with all the letters laid out. so you can't have 2 B notes, you'd have to keep flatting and sharping it. the same would be true for E#, which would be the last note the key of F# major. if you called if F it would be a mess when you write on the staff, you'd have to keep sharping and unsharping the F