Trombone, Sax, Tuba, all of which I have had experience with. I played Trombone for a good 7 or so years, and it was much easier to get into compared to guitar. Sax was even easier for me.
With guitar, you have to get the chord fingers perfectly, even down to the position they are on the fretboard. All the other instruments I've played are much simpler. Guitar is complex and requires much more practice to get in good shape.