David Hilbert
The bright young newcomers who saw the famous Hilbert in action for the first time at [the Mathematics Club meetings] were struck by his slowness in comprehending ideas which they themselves “got” immediately. Often he did not understand the speaker’s meaning. The speaker would try to explain. Others would join in. Finally it would seem that everyone present was involved in trying to help Hilbert to understand.
“That I have been able to accomplish anything in mathematics,” Hilbert once said to Harald Bohr, “is really due to the fact that I have always found it so difficult. When I read, or when I am told about something, it nearly always seems so difficult, and practically impossible to understand, and then I cannot help wondering if it might not be simpler. And,” he added, with his still childlike smile, “on several occasions it has turned out that it really was more simple!”