5 impediments to critical thinking

Answer 1

laziness
inability to comprehend
resistance to new knowledge
mooching homework answers
thoughtlessness

Answer 2

Also check this site.

http://www.scottsdalecc.edu/ricker/critical_thinking/CT_resources/CT_impediments.htm

Answer 3

Although a resistance to new knowledge, I might list these separately:
prejudice
bias
Preconceived notions