Wrong notes

 Victor Wooten says you are never more than a half step away from a right note. Monk says none of the 88 notes on the keyboard are wrong notes. The worst possible note is probably the fourth played against the maj 7. So play CEGB in the left hand and F in the right.  That sounds pretty terrible. But against a 7 chord (Bb) it sounds ok. 

You can play every note in the scale and except for the fourth and the seventh, and you have a pentatonic scale. Think of the beginning of "Someone to watch over me."  You can pretty much improvise over the blues with six of seven notes. 

All the notes that aren't in the key are chromatic leading tones or chord alterations. So a wrong note can be corrected by playing a right note right after it.  

Improvisation is easy then.  The caveat is that there is no guarantee that the ideas you play will be any good. Here other factors come into play. You have to play with rhythmic dynamism.  The improvisation cannot be too random, or too predictable. You have to have enough technical ability to play what you want. 

The best thing is to find that you have played something that you liked.  Then you can use your own taste as the guide.