It is true that the vast majority of solar eclipse folklore, myths and superstitions are looked upon in less than favorable light.
Throughout history, solar eclipses have been viewed with dread and associated with myths and superstitions. Even today, in the 21st century, some cultures consider them a bad omen.
It is not completely surprising that the phenomenon has been such a source of fear. A total eclipse, especially, can be a disturbing experience - something that appears to undermine nature itself. - UK solar eclipse 2015: Ancient myths and folklore surrounding the phenomenon
But that said, it is possible to find some cultures that look upon an eclipse in a more favorable light. The most common one found on the web is the one that is mentioned in Yannis' answer.
In Italy, it is believed that flowers planted during a solar eclipse are brighter and more colorful than flowers planted any other time of the year. - Janet’s Planet: Solar eclipses inspire myths, superstitions
But why stop there. The Old Farmer's Almanac has the following tidbits to add on:
A Solar Eclipse and Romance
Many cultures thought that the Sun was in a fight with its lover, the Moon! Others found a different kind of romantic explanation.
•To the Australian Aborigines, the Sun was seen as a woman who carries a torch. The Moon, by contrast, was regarded as male. Because of the association of the lunar cycle with the female menstrual cycle, the Moon was linked with fertility. A solar eclipse was interpreted as the Moon-man uniting with the Sun-woman.
•In German mythology, the hot female Sun and cold male Moon were married. The Sun ruled the day, and the sleepy Moon ruled the night. Seeking companionship, the Moon was drawn to his bride and they came together—thus, a solar eclipse.
•Some Native Americans drew on a similar concept: that a solar eclipse was a visit of companions.
•West Africans of Benin switch the gender roles of the Sun and Moon and suggest that the orbs are very busy, but when they do get together, they turn off the light for privacy.
•In Tahitian myth, the orbs are lovers who join up —providing an eclipse—but get lost in the moment and created stars to light their return to normalcy.
Eclipse as a Good Luck Charm
Eclipses did not incite fear in at least one group: Bohemia’s miners. They believed that the event portended good luck in finding gold. - Solar Eclipse Folklore, Myths, and Superstitions
Not all of the folklore associated with eclipses are negative. One surrounds Herodotus, an ancient Greek scholar, and a battle in the 6th Century B.C. between the Medes and the Lydians, which was raging until a solar eclipse began, for the gods were displeased with the war.
". . . there was war between the Lydians and the Medes five years. . . . They were still warring with equal success, when it chanced, at an encounter which happened in the sixth year, that during the battle the day turned to night. Thales of Miletus had foretold this loss of daylight to the Ionians, fixing it within the year in which the change did indeed happen. So when the Lydians and Medes saw the day turned to night, they ceased from fighting, and both were the more zealous to make peace." - Eclipse Quotations - Part I
Addendum: There will be a total solar eclipse on August 21, 2017 that will be seen in North America.
