I mean, my requirements for mint condition are just what the term "mint condition" is defined as in the case where they are in the same condition they are in when they were opened from the pack. I never had issues with creases, tears, and stains, but I definitely had a lot of issues with scuffs and scratches. Usually not severe enough to be clearly visible when initially looking at the card, but were visible when examining the cards more closely in natural/good lighting.
I did ask for pictures every time, and I did have a few successful trades/transactions as well! I think I was at fault for some earlier transactions when they didn't give me the best photos/videos of the cards, and at the time I thought those were good enough until I received the cards in person. As for most of my other experiences, I feel that a lot of the cards came poorly packaged. Some didn't even have sleeves, and I also had this one instance where someone jammed 3 cards into a single top loader (sleeveless).
<- I also feel like I was somewhat at fault for not doing enough research.
I forgot exactly what happened, but I either didn't ask how they were packaging the cards ahead of time, or wasn't aware that 3 cards was way too much for one top loader.
Throughout my spree I remember checking TBT multiple times and considering trying out some trades, but all the bad experiences I had from other sites just made me feel discouraged. It's difficult for me to trade/buy since I jump back and forth between my parents place and the place I rent out when I need to attend my classes (I usually leave my collection, binders and sleeves at my parents place), but like I said above, if I ever decide to get back into trading I'll look into the forums first. :0