Heh, awesome
Probably depends where you are tbh
Where I am you might get the occasional wasp and that's it (so more often then not, no bugs buggering your picnic).
Then I want to live where you live! Virtually no bugs during summer sounds like heaven
But yes, e.g. if the author lives where you do, it's not a given they'd think about bugs when constructing a milieu with swamps, pines, moose, and no seas nearby. Besides, fantasy is fantasy, it's a fantasy setting, it can be virtually bugless and birds would still have food, certain plants wouldn't depend on bugs for pollination, etc. Also, there's the thing as you pointed out, the relevance for the story. While in my mind it attributes to the mood and realism (which I value quite high), from someone else's POV other things are more important.
Heh, funny thought: maybe the absence of bugs could also be explained by the vast amount of British fantasy writers? j/k, but seriously, I've only been around England (not e.g. in Scotland), and there weren't noticeably many deer flies, black flies, tics, mosquitoes, horse flies, or large pine weevils (that are just gross, btw), and other such wondrous examples of the beauty of mother nature (I'm getting flashbacks from the South Park episode 'Rainforest Shmainforest'). There were ants, though.
As for the *cough* rest, well as long as you arrange yourself right, it's mostly not a problem and let's leave it like that
One of those things that it's just as believable either way, to me, from experience. Can't say I've ever ended up with mud in my nethers! Fern once...Sticky patches
can be a problem where ever *again cough* but if they don't serve the story or add anything, I can understand not putting it in (it's a matter of subjective taste whether to or not). But if my I needed to, to serve the story, that's not a stretch either.
While mud can go to the nethers, I meant something else from a more... manly than muddy source. But, again, these details don't
have to be there, but I sure wish someone pointed out the nuisances every once in a while
(like if you do it in water, well, turns out there's a reason why people do
not use water to... enhance the slide of the sleigh...) Some of these simple things
could be used for more or less amusing silliness -- or even tragedy
*gets a vision*
But as you and others have pointed out and implied, people have different, even contradicting experiences of certain things and while some simple thing seems oh-so-wrong to some, they may make or break the scene for others.