I love beginnings, I rarely get to endings. What happens in the middle is hard to pace for me. Might be easier if I followed the Hero's journey or other meta-narratives, but I like to write character first. So the middle of the story is where I want to put the characters out in the world and see how they do, what they do, without a conscience reference to the main plot. So for me, when I get to the middle of writing a story it can really meander.
How about yourselves?
I usually have an ending in mind and some middle bits and it's the starting and putting it all together that's the hard part.
Interesting. The best advice I've seen is "start late, finish early." Basically starting en media res, cutting out anything that isn't necessary for hte meat of of the story.