Biggest disappointment

The concept was so good and then it went all cliché and turned itself into its opposite. 

The good parts were amazing, the bad parts were dangerously bad. Like, teaching kids about consent and boundaries one ep and violating these very principles in the next. Dangerous.

I don't get the hype, there wasn't a single tomb here, scenes were copy-pasted from earlier seasons and everyone was acting stupid. 

It was such a nice and calm bedtime drama until they triggered all the wrong spots for me and the relationship turned bland. 

Nice concept, great OST, but the plot was a mess

Someone was on some bad substances when they wrote the ending. 

This. Was. Not. Scientific! The presentation of this drama's methodology of science is a danger to society because people believe that for real.