Bluffers Guide to Playing Jazz
Yup, notes are the problem. How many to play, which ones, and at what time.
Guitarists are known by their desire to play one or two extra notes on their instrument after the song has ended. This works well in the early part of the gig, but sooner or later the drummer notices what happens and will cover their final odd notes with a short flourish on the drums. Later still, the alto player joins in. In the hands of professionals this becomes an extended improvised coda which surprises everyone since it bears no relation to the song at all. Guitarists try to sit next to drummers but a long way from pianists. There is no known reason why. Perhaps it is because pianists can use all ten fingers at the same time.
This is one of the most difficult bits in jazz to do properly. Some bands are on record as not knowing how to do it at all, and once the final melody has been played out, someone then strikes up with another solo. (True) This makes for fascinating and meaningful social interaction within the group. This is one reason why audiences prefer to watch jazz players rather than listen to them.
Knowing where the 1 is tests the mettle of all soloists. For some of them, listening to the music itself is of little help, and they need someone to nod them in on time. Singers are particularly prone to starting problems and frequently offer themselves to band leaders who look after them in this regard.
Playing duff solos
If you play a duff solo it is because you have forgotten where you are in the song, or forgotten what key you are supposed to be playing at that moment, or because you are out of it anyway. After you have finished everyone goes quiet - although everyone knows where you went wrong and will talk about it behind your back. The thing to do is to ask the band loudly, "Did someone cross the beat at bar 23?" The band will look at the drummer, who will say "Sorry" and you are off the hook.
Drummers usually take up the instrument as part of an anger management course. You can't play as many notes as a drummer plays and worry about what key you are in as well. There are too many jokes about drummers, too often told in public announcements for them to feel totally at ease at all times. A bit of tlc to drummers pays off.
Double bass players have feelings of insecurity, and carry their instruments to gigs as self-abasement. They feel bad because they always play far fewer notes than anyone else but receive the same money. They are given occasional solos to play because the rest of the band want a lift in the van going home afterwards. The bassist will love it and will smile shyly if you tell him that his is the most important instrument in the band. This has the advantage of being true, unlike everything you say to everyone else about how good they sound. Sincerity needs to be practiced.
Classical musicians playing jazz
Jazz players all have feelings of self-doubt when they play with classically trained players. Jazz workshop groups sometimes attack classical newcomers immediately by advising "Just follow the 2-5-1 progressions, dropping down to a minor third in the bridge." They then destroy the classical player by taking their music away from them, and immediately starting in the count in. Professionals raise their game here by saying, "Let's do it in Gb" and then starting the count in, in double time.
The way for classical musicians to get their own back is to suggest that the piano or guitarist plays the melody. These people can only read chords and not dots so they are cooked.
Pianists are up against time. They know too much. They know about harmony and chord progressions. They have to make a decision between 786 different chords and voicings, plus substitute chords, they have ten fingers to use and the possibility of using any of seventy-four scales. They are also the only people who can see every note they are going to play, which somehow contrives to make the problem worse. A fast swing piece at 240 bpm with two chords in each bar means they have 0.5 of a second to decide whether to play the altered chord, or the diminished chord, or the straightforward dominant 7th or maybe even a flat sixth triad in the upper structure and how to voice it and which inversion to use. (Which fingers on which notes) In addition they have to do something interesting with the fingers of their right hand. This all may seem a bit technical but it indicates why there is so much turmoil going on inside pianists heads and why they all end up playing by ear like everyone else after the first four bars. It is little wonder that they are bald and introverted. It is also the reason why they are so condescending to the rest of the group.