Well, I've certainly never given birth to a child, or anything nearly as challenging as that, but I've done plenty of hard things. When I think about triathlons I've competed in, they weren't easy, but at the moment when I crossed the finish line, there was nothing but joy. The same is true for graduations -- I don't get dragged down by exhaustion from work that was done, but celebrate the accomplishment.
In this life, there will be plenty of challenging moments. We will undergo suffering and trials, both in our own lives and those around us. At times, we'll likely wonder where God is and what God is doing. There aren't often easy answers in those moments, but God promises us that those will pass, and that the fullness of joy is awaiting us on the other side of our suffering. One day, there will be the fullness of joy, and the hope of this is what helps us push through the dark nights of the soul that we face. Like a traveler on a lonely road in the dark of night, we wait for the dawn, knowing the stone has been rolled away and the tomb is empty and we shall rejoice together one day.