As others have said, a limit not a target. But also, how fast you can travel along a road sensibly very much depends on conditions. If you do let people think of the limit as a target, you'd better set the limit low enough that it's still appropriate in terrible conditions.

As a specific (and horrific) example, this doctor was found to be mostly liable for a collision that happened due to her speed, while still under the speed limit: https://www.bbc.co.uk/news/uk-england-oxfordshire-66121540

My general take is that I try to drive as if a maniac (meaning anyone who might think it's reasonable to drive faster than I do) is about to come the other way along the road. I should be able to stop within my sight-lines if the road is wide enough to take evasive action, and well within half that distance if the road is narrow.