-Unstable test cases
-Tests that you will only run only once.
-The only exception to this rule is that
if you want to execute a test with a very large 
set of data, even if it’s only once,
then it makes sense to automate it.
-Unfinished functionality
-Visual test cases
-Also Tests that need to be run ASAP
which usually a new feature which is
developed requires a quick feedback
so testing it manually at first making sense.