Spencer Pratt: Being a Father Has 'Definitely Made Me Enjoy Humans' — Even Ones 'I Can't Stand'

"Even the people I can't stand, they were once sweet little babies," Spencer Pratt tells PEOPLE in a segment of Celeb Parents Get Real

First-time fatherhood has taught Spencer Pratt a lot since welcoming son Gunner Stone with wife Heidi Montag in October.

“My son Gunner definitely takes after Heidi because he comes off genuinely sweet. He just seems like the sweetest little baby,” Pratt, 34, tells PEOPLE. “He’s always smiling. I feel like I would be a grumpy baby.”

And Pratt admits his most embarrassing parenting experience also got him a bit grumpy. “I would say the first time my son peed all over me and it was just really hot. I was adjusting to being urinated on, so that was like, ‘Oh, there’s hot pee all over me,’ and I kind of acted like a baby.”

“I ran and showered. I’ve been peed on since and I handled it way better,” he says, adding that he’s learning to be more patient and advising, “You can’t get frustrated.”

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Though parenting calls for some tough times, The Hills alum reveals there are rewarding moments as well.

“My favorite part of fatherhood is seeing a baby so innocent. Until you watch a human being born and watch a little baby growing and learning how to smile and waiting for a baby to giggle … it’s definitely made me enjoy humans more,” he says.

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Pratt continues, “We were all little babies. Even the people I can’t stand, they were once sweet little babies. What happened to them?”

As Pratt and Montag, 31, continue to revel in new parenthood, the father of one admits there are parts of his life before Gunner that he does miss.

“I used to love going to the movies. I used to love going out to dinner, being able to just leave the house. Not like packing strollers and multiple bags and car seats. It’s definitely a mission leaving the house now,” he says.