why is it that this sounds out of the chord

Buco

Reinier Voet has, in one of his 50 Gypsy Jazz guitar licks video series, the easy way to get into "outside" playing. Basically if you have a full bar or more of the same chord, you can play a lick in key and then move a half step or a fret up and play the same lick and then go the other way, half step down and play the same lick, eventually resolving by finishing the lick back in key.

Jazzaferri

Kenny Werner did an example something like that years ago when he demo'do playing I can't remember which jazz standard in the regular key with his left hand and the melodic line in the key a semi tone up. It actually sounded pretty cool.

Lango-Django

you can play a lick in key and then move a half step or a fret up and play the same lick and then go the other way, half step down and play the same lick, eventually resolving by finishing the lick back in key.

Works with chords, too.

This was an old trick favoured by Eddie Lang when the harmony stayed in one place for a few bars, usually on the tonic chord.

He would simply move the whole chord up or down a fret or two, eventually coming back to the correct fret.

Try this when backing a solo instrument, but it may not work as well if there are any other rhythm guitarists playing along.

Strangely enough, you CAN get away with doing this when playing along with a pianist who just stays on the tonic chord while you are jumping all about.

I don't know why...