What tests should we automate?

Some testing type's needs human attention and intelligence, but most types of testing benefit from automation. In the same time QA Engineer should automate only that which needs automating. No one can automate 100 percent of testing work, but in certain areas like performance testing, load testing, stress testing regression testing, your team may have chance of reaching near to 100 percent of test automation. Other areas of easy automation would be API testing, test data set up and creation.