First Edit: Your Favorite Mug/I Didn't Mean To...

[nozaki]

Your Favorite Mug

It landed on the floor
like a fat skull.--fat skull, hmm? had to think about that for a second, since to me, a skull is inherently devoid of fat. 
The pieces large enough
that I could glue them-
fixed,--weak on its own, I think. maybe bring it up to the previous line, so reading, [that I could glue them- fixed-]
but with subtle cracks--could do better than subtle. maybe pale? delicate? gauzy? just the feeling I get. 
you would always know were there.--perhaps insert [so that] at the beginning of this line. 

i think the title is a little childish / uninspiring but it works, i guess. this entire poem reminds me of a japanese concept called kintsukuroi, or fixing cracks such as these by filling in them w/ gold. the ending is my favorite part, there is something intriguing about fixing a favorite thing but not all the way, as if intending some type of petty revenge. not sure if thats where you were headed, however. enjoyed the read, do continue.