"I'm comparing my playing to others", I hear you say which is very true.
When we compare our spontaneous music making to the written masterworks of old masters or to the splendid videos of distinguished virtuosos we see online, it's evident that there is only a small chance we can create something of that level so easily.
Which is fine if we forget how many years of focused practice of trial and error the old masters and virtuosos needed in order to become what we remember them for.
Another frequent response I hear is this: "I don't know, if I'll like it".
That's just the outside but deep inside the meaning is different: "I'm afraid, if I'll like it, I'll have to change - from performer to creator". That's a scary thought indeed.
To change from the person who follows the rules to the one who creates the rules.
More productive thought would be to suspend the comparison and the fear just long enough for you to try and fail.
After you tried and failed at least 100 times you can decide, if it's for you or not.
[HT to Simonas]