There was absolutely nothing special about Ethiopia. However, take a look at this map of Africa in 1913. The only area that was not already colonized by a European Power is in white. What do you know; that's Ethiopia!

Italy was only unified in 1861 and was late to the colonization game so could only pick up what was left (the Tripolitanian coast and the islands of the Dodecanese from the Ottomans, plus Ethiopia over the course of three wars). Italy had already gone to war with Ethiopia in 1868 to seize Eritrea prior to full annexation in 1936.

Now, why did Italy want any colonies at all and picked on Ethiopia as a result? Well that's a wider issue to be taken within the context of European Colonialism in the 19th century.