The Importance of Being Earnest is first and foremost a farce, a comedy of manners whose main goal is to amuse the audience, rather than to make them think.
Spring can symbolize Re-birth, Beauty, Growth, and even Joy~
Examples of irony:
An inoperative tow truck that needs towing.
A firehouse catching on fire.
A skydiving instructer jumping out of a plane without a parachute.