You are going to laugh--some of you more than others. After resisting the piano my whole life, I have finally given in and for the last few weeks, have been teaching myself to play. The piano. Not a real one, of course, but a digital electronic keyboard that I can plug into my computer and link up with my music software. But it does, among a bunch of other sounds, have several piano sounds.
I had a lot of not-very-plausible reasons for avoiding the piano: it just didn't appeal to me, aesthetically. Rather than an expressive musical instrument, it felt more like a piece of furniture. Later on, after I had become a classical guitarist, the nails on my right hand interfered with good hand position on the piano. Also, for quite a number of years, trying to use my right hand on the piano felt awkward to the point of being painful. As someone who was a professional classical guitarist, it just didn't make sense to work on an instrument that seemed incompatible. I suspect that other incompatible instruments would be, for example, the oboe and brass instruments as the embouchure is completely different.
But as nowadays I am largely retired from playing concerts on the guitar and devote my time more to composition, the situation is different and it makes sense to do some work on the piano as an aid to composition. I'm not sure how much difference it will make as I have never really composed on an instrument, only checking things out afterwards to see if they will work. But working to learn a bit of piano technique is interesting in itself and gives one a different perspective on music. I think that guitarists have a somewhat idiosyncratic approach to harmony because of the instrument. On the other hand, I wonder if pianists are not somewhat restricted in their understanding of certain kinds of expression because of their instrument. As a guitarist I have always been able to bend the pitch of any note (except for open strings) and to change the timbre as well. I can also apply vibrato to most notes. If you see a guitarist, or someone who has played some guitar, playing piano, you might catch them occasionally trying to make a note vibrato by wiggling the key--ineffectually, of course. Mechanizing the production of notes on the piano has meant giving up the ability to control certain expressive aspects of the note.
I'm an odd sort of piano student. For one thing, I can mostly teach myself, though at some point I may get my hand position and technique checked out by a real pianist. It is challenging sight reading on piano for me for several reasons. One is that I don't get the same kinesthetic clues as to where my fingers are that I do when playing guitar. Because I am holding the instrument I pretty much know exactly where the frets are. On the piano I don't have that same feeling of unity with the instrument. Also, little clues from the curvature of the neck and the angle of my arm enable me to localize which fret I am on, but to my finger, all the white keys on the piano feel the same and I have to glance down to be sure where I am. I guess this will improve? Other things that are different are having to read two clefs simultaneously and the different relationship between the hands. On the guitar the hands always have to be coordinated in the same way, with the right hand initiating the note while the left hand stops the string. On the piano, you coordinate the hands rhythmically, but the feel is totally different.
What excites me about playing piano is the enormous harmonic freedom. Things that are awkward or impossible on guitar are easy on piano. Any inversion of any chord is as accessible as any other. The sheer facility of the piano is compelling. I'm starting to sense how the fine control of the mixing of the notes of the melody and harmony is where the expression lies on the piano. The equivalent on guitar is those subtle alterations to the angle and stiffness of the finger as it plucks the string that give a spectrum of different "colors".
But probably the biggest thrill is that all that music for keyboard that was only somewhat available to me as a guitarist is playable on the piano. Well, after I do a lot of very dull work on scales and arpeggios, that is! This is the only downside I see: in order to have even minimal technique on piano, I will have to do a huge amount of work. And my right hand will, as a result of being a guitarist for over forty years, always be weak compared to my left hand. Still, I've already had the fun of playing through the first twenty or so pieces in Bartók's Mikrocosmos...
Most of that is modal music in octaves, which seems to be a great way of getting the hands organized to play together.
I'm also coming to understand that part of my aversion to the piano was simply that I found it an intimidating musical instrument.
Now I have to go practice!