Q: Why are frogs so happy?
A: They eat whatever bugs them!

Explanation:  Bugs– those bothersome little insects.  If something “bugs you” that means that something irks you, bothers you, pesters you, annoys you, is bothersome to you, …

Frogs eat bugs, that is, insects.  Therefore, frogs eat the bugs that bug them which, in turn, makes them happy.  (My grandpa was happy when eating frogs – frog legs.)

A silly joke that plays with the word “bug.”

Winnie The Pooh would often say, “O bother” when bugged by something: