My biggest problem has deffinitely been tempo. If I am playing a solo, it is not a big deal. However, when playing in a group, many times piano will do the intro, and even after all these years of playing, I still find I have a tendency to rush the tempo!

Well for me I find the stacatto fast accords very hard and need a lot of time to master it

Been so long since I "learned" to play so I really can't recall. I was somewhat a prodigy, the quit for a number of years as a teen and since then the challenge has been regaining consistent technique...

Recently the problem has been tennis elbow - I hurt my elbow playing tennis, but after some gear adjustments tennis is no problem. But using a computer mouse (I am a professiona computer programmer by day) irritates the injury as well as trying to play challenging piano pieces. A couple Chopin Polanaises I recently tried to hack through (Heroic and Military) have some nice easy chords in them that made the tendons in my elbow say "no mas"...

So I've had to take a few weeks off, now I'm slowly getting back to playing but concentrating on my own pieces where at least I can limit how extreme I stretch. Of course, with my tendency to hack out on some of the hardest pieces around I've learned some really nice bits of technique to apply to my own pieces, so my elbow still sometimes cries out a bit.

But it's getting better, so soon I'll be back to just trying to recapture the effortless technique I used to have a kid. Every once in a while as I'm improvising some explosive stuff comes out to remind me I can still do it, albeit for only a few tens of seconds at a time!

learning all the scales was easily the hardest part for me. ive been playing since i was tall enough to reach the keys, and i still find them hard to remember

EV - I once played bass in a jazz trio where the piano player could sight read Kieth Emerson transcriptions and take my lead-sheets and play the piano like I wanted to. We were struggling trying to work out one of my pieces, when I said something like "well, I wrote it in B, but figured it's easier for your in C"...

He laughed and simpley said "Let's play it in the key you wrote it in. All keys are the same". It took a while for his words to take effect, but he's right - all the scale are exactly the same. Some might present an individual with physical issues (I personally have a problem crossing my RH middle finger and thumb between A and Bb in an F major scale), but remembering the scales in different keys should not be a problem. A major scale (in general, not the key) is the same relationship in any key. If you can understand what a key signature means it should guide you playing a scale.

Now remembering all the different scales...that's a different nut: major, natural minor, harmonic minor, melodic minor, all the modes, other strange things...whew!

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From Dr J: Or is it finding the time to practice?

That's always an issue too...I decided tonight that I had to write out a riff I was jamming on the other night...I might end up writing out the piece all night on the computer rather than actually playing it!

It is finding time to learn how to play the piano. When you are younger, you have the time to really learn. When you are older, you are weighed down by a lot of other preoccupations.

I dunno how to memorize the notes. Meaning, I can't play unless there are notes in front of me.
My sight reading isn't that bad. But when I'm given new notes, I can't play them with both hands right away.

The hardest thing for my is rhythmn.. i really suck at rhythmn. Also sight reading both hands for me is difficult.