Questionable Qualifications
Many people love debating with randomers on the internet. It’s a pointless exercise because nobody turns around and says that the other person is correct. Everybody shouts into the void and hopes to get more likes than their rival. But one of the worst tactics is to question another human being’s qualifications.

This is very risky because it can backfire like in the situation above. One person thought that they destroyed the other but he didn’t realize that the dam was about to burst open. The number of likes on the reply shows how effective it was. Also, be careful debating somebody with a blue tick on Twitter because it’s easier for them to gain momentum (via Reddit).