-The subject matter is likely to be mostly to totally outside of a person's technical depth and factual experience. (Here I try and think if someone asked me to decide some question related to something like advanced particle physics, chemistry, or the tax code).
-There is not that much time to figure out what is going on (these trials tend to last less than a week of 7 hour days).
-There are many different complex topics being addressed in that time span: the patents, what is being accused, etc.
-What is said is being said by competing groups of apparently competent people.
-Those people are saying widely different things about the aforementioned complex subject matter.
-Everything is being said in an extremely serious environment (Federal Court) which lends substantial gravity to each side.
-Jurors are not to consult information beyond what is presented to them in court.