Tragicomedy
Let's begin with the tragic. Winnie finds herself in the same situation—or perhaps worse off—at the end of the play. Winnie and Willie have no control over their situation. In fact, the play might end with a murder-suicide. Sounds pretty dire. And yet, we can't help but laugh with (and at) Winnie and Willie.
Time and time again Winnie makes light of her situation, and we, being the empathetic audience members (or readers) that we are, can't help but join in with Winnie and her terrible situation. Or as Verna Foster, a leading critic on tragicomedy, says, "when we laugh at what is funny, we are simultaneously laughing at what is tragic" (source).
The line between tragedy and comedy has always been a thin one, and no one makes this more obvious than Beckett. As with other tragicomedies, in Happy Days the audience is asked to question the link between tragedy and comedy. No doubt, Winnie's situation is tragic, but Beckett approaches it in a comic matter and, ultimately, isn't that what life is all about?