Any and every strap, belt, harness, string, cord or anything else that can catch, get tangled, come loose, twist, or snag. [:@]
this includes but is not limited to-Bino harness, safety harness, foot straps on climber, and the strap that holds the top & bottom together. [:@]

In a related note, forgetting the strap that holds your hang on to the tree also can be quite frustrating. Especially when you are 2 hours from home, have as hot a scrape as you've ever seen, and the only ability to hunt it effectively would be from a perfectly selected tree 18 yds away. [:@]

And getting an itch in an inappropriate places when you have 3 layers of clothes & gloves & a safety harness that gets in the way. [:@]

Those are the little things I can think of now. I have plenty more to complain about, but those I would consider "large" complaints.