Can a Legendary or Rare item be found in any clickable object such as a jug, barrel or a crate?

I want to know if it is worth clicking on every object I see.

Empirically, it seems that the jugs drop less loot than barrels, and I ask this because I haven't found any good loot from them yet.

Yes, the lowliest barrel can drop a rare or a legendary.

Blizzard has said so many times and many people have found incredible loot in otherwise lowly containers. Of course, a rare monster has a much higher chance of dropping good loot than a barrel, but there's a chance nonetheless.

Based on my knowledge the destrucible objects like jugs, barrels and so on can drop rare items too. Unfortunately I haven't found any kind of legendary or set item (not even from a boss and I'm level 60 and on Inferno), but I got several rareitems from those stuff. So, yes, it may be worth destroying them.