What part of fatherhood do you find toughest?

As I mentioned earlier in the week, our youngest is going through a sleep regression at the moment. He's almost two, so this is all normal, but I had forgotten what a lack of sleep does to you. Waking up in the morning feeling drained rather than refreshed, your body straining with the force of a dump truck full of bricks emptied onto it, and finding it impossible to do even the most simple tasks throughout the day.

I've been trying to drink less this year. And honestly? It hasn't been working. But maybe sleep deprivation will be the thing that does it. Because the only thing worse than waking up at 3am to a screaming child is trying to do it with a hangover.

You know what they say—a problem shared is a problem halved. Or perhaps more pertinently—misery loves company. So I want to know: What part of fatherhood do you find toughest?

As always, I'll start, and look forward to reading yours in the comments.