Yesterday I was chatting with a colleague who has 2 small children. We started around the same time and have both been evaluated pretty positively since we joined the company. At the end of the year I got the opportunity to do a new work thing and I accepted this even though I'm now realizing that I am really working at the limits of how much work I can do. She got the same offer and declined. With a heavy heart because it was something that she wanted but with kids that are smaller than mine (and sleeping very unpredictably) she was afraid she would disappoint people because of not being able to deliver what people expected. And because she was afraid she would be exhausted literally all the time.
I've made similar choices when my kids were babies (and am actually still making this choice by officially working 4 days a week instead of 5). But I also realize that declining such an offer before even trying means that perhaps you're missing out on something that could have worked out. But I can also definitely see that the prospect of being exhausted/underperforming makes you opt out. And I'm guessing there's probably a gender difference here. And a bit of perfectionism?
Have you declined opportunities because you were afraid they would be too taxing?