1. Lack of technique
2. Lack of skills in sight-reading
3. Lack of skills in music theory
4. They lack courage
I empathized with him remembering the scariest experiences of improvising during my 1st year of studies at the aforementioned Academy. For some beginning students, improvisation was even more terrifying than to me because they were asked to improvise Passacaglias on their 1st year without having developed good hand and feet coordination.
I pondered about these challenges while listening to Deimantas play. He was prepared to try out Buxtehude’s Passacaglia in D minor. As he played this beautiful piece, I thought he was underestimating his skills. His playing was slow and careful yet clear which demonstrated his skills to play several independent melodic lines at the same time.
I also explained to him the structure of this Passacaglia (7 variations in D minor, 7 - in F major, 7 - in A minor, and 7 - in D minor). After this, his eyes sort of opened and he began to see composer’s intentions. In a way, he started to understand how it’s possible to communicate in this musical language and tell a musical story using Buxtehude’s style. What’s even more fascinating to me is that we both agreed that I didn't show him anything extraordinary that he with his current theoretical understanding wouldn't be able to find out himself.
It turns out that the main thing which scared him from trying to improvise was his own lack of believe in his skills and the preconceived notion that the cost of making mistakes is too high. This may be true when we walk across the street and get hit by a car but in music making, every mistake can lead to even greater musical discoveries.
Out of any of the organists I have met who don’t improvise yet, there was not a single one who said improvisation wouldn't enrich their lives. Everyone agreed that having such a skill at their disposal would be a cool idea. So all you need for starters is curiosity to try and understand that mistakes aren't going to kill you.