13 things that do not make sense

New Scientist magazine has a list of "13 things that do not make sense". Their titles include:

The placebo effect, Belfast homeopathy results, The horizon problem, Ultra-energetic cosmic rays, Not-so-constant constants, The Wow signal, The Kuiper cliff, The Pioneer anomaly, Viking's methane, Dark matter, Dark energy, Cold fusion, Tetraneutrons

As you read the article, notice how often words that indicate an expectation are used, such as:

should be, there must be, theory predicts, theoretical limit, not what we expected, etc.

There is an answer for all these mysteries, but it's probably not something the scientists want to hear...