Poorly tied knots, being discovered and saved.
For ropes:Cotton, polypropylene, hemp, jute etc, they all have heir pros and cons. I think cotton is more than strong enough for full suspension too, but it's still weaker than the others. I'm getting a hemp rope preferably because I can stash it away secretly and it won't really deteriorate. Actually I'm getting several ropes, maybe a cotton one, too. I'm even going to use strong tape around the anchor point on the knot, etc. leaving no stone unturned lol. Maybe you could practice blood choke yourself so you know best placement that works. Hope that helps. Maybe alcohol and paracetamol ,etc, could also help ease si and discomfort.