Worst grid ever

That is much too harsh. It was very tricky though, 0/10 for me.

I agree with Aetees that Joe's comment is too harsh, and offers no constructive feedback which isn't helpful at all. I really like some of the ideas here, but I just think the connections are all so specific (and, in some cases, such as the "Feet" group, too broadly defined) that very few people would ever work them out. Combine them into a grid together and this grid feels almost impossible.

1/10 for me. I agree that it is too hard overall, but I don't think any of the individual lines is particularly unfair... just without an easier one in the bunch, there's no place to get started.

The "clock" group would be much stronger if the words all shared a common vowel to begin with. The "work" group is fine but I feel like any group that has a "prefix" or "suffix" connection is stronger if all of the members form compound words or all form a common phrase, not a combination of the two. It's easy to underestimate how hard it is to see those connections in the first place without adding the wrinkle of inconsistency within the group.

The animal category gave me a point when I guessed "Agatha Christie"

I don't know of any one person could figure this one out in 10 minutes let alone 3. The author wasn't fooling around when they marked the difficulty as "fiendish". I actually really like every one of these categories, just not all together in one wall.

Badger line is good, but overall either far too obscure or too arbitrary to allow a foothold into it. A bit more generosity.