I get a lower score when I "eliminate render-blocking resources"

[Sara Barats]

I'm brand new to PageSpeed, and I'd like to know why this is happening. It happens with other metrics as well. I am also unsure of what files are safe to defer, and what isn't.

[Lauren Gray]

Hey, Sara, this can happen when deferring those assets actually makes your site take longer to visually load. For example, if you defer your CSS without adding any critical CSS, your site will flash from unstyled to styled and that can drive your paint metrics up, leading to a lower score.