Why Are Physicists Bad In Bed?

Jo asked me this today. I came up with the following:

Because a femtosecond is a long time to a Physicist.

Because their length contracts when they go faster.

Because the more energy they have, the shorter their time period.

Because they can't solve the 3-body problem (thanks XKCD).

Because they don't know what goes on inside black holes.

Because they're not MACHOs.

Because they're a Bohr.

Because they can't carry any force when they've got a fermion.

Because their oscillations lose energy quickly when damped.

Because they tend to Bragg.

Because they follow the principle of least action.

Because they find that repetitive motion Hertz.

Because their Planck length is only 1.6x10^-35 metres.

and, saving the best until last:

They're uncertain since someone interfered with their Young slit.