| If the value is over $100 or the weight is over 1 lb, you have to fill out a larger, more detailed form. If anything goes wrong with the transaction, such as damage during shipping, there are huge delays waiting for the package to be returned, or the paperwork to be processed, and very often an international claim will be rejected on the basis that it may have been damaged by the foreign carrier agency. Lost packages are nearly impossible to find. And even when everything goes "right", there can be delays of days, weeks, even over a month sometimes at the customs office in the other country, resulting in confused or angry emails from the buyer, maybe even negative feedback. Plus shipping is so expensive, if there is any dissatisfaction on the buyer's end, they lose the cost of returning the package to the seller, and the seller loses the cost of the initial shipment. On both sides that money is gone forever. If it's a $2,000 item it's no biggie I guess, but if it's a $150 item and the shipping cost $40, that's a hard pill to swallow for both parties.
I've sold dozens of items internationally with no problems, but in the few cases where things didn't go so great, it was a lot of heartache. | 
