I see a lot of different opinions here, from very positive to very negative.

I think the answer is, it's both.

When I was an employee sometimes I was happy, like when a promotion was lurking, and sometimes I was unhappy and stressed, when getting fired, when facing deadlines, ....

But when I started working for myself the amplitude of emotions became way stronger, every week I would fluctuate between feeling doomed forever or feeling like a genius.

Life with and without kids is the same: The emotional highs of having kids are way higher than anything I experienced without kids, but sometimes the lows are very low.