Hummer BT, Li XL, Hassel BA (2001) Role for p53 in gene induction by double-stranded RNA. J Virol 75:7774-7777, Figure 4

What's wrong with this one?

The bars and little antennae represent just three data points each.

What should have been done?

With just three data points in each group, why not just show the data as dots? You could also include line segments at the averages and even confidence intervals...all this in the same amount of space and with less ink.