If they ask if i'm looking for anything in particular I tell them i'm looking for the Holy Grail but your gold, silver and priceless antiques will work have to do for today.
Or in reference to ebay... you better sell it on ebay then if it's worth that much, as I'm walking away shaking my head (mumbling idiots under my breath).
Other customers... mostly I just laugh at them because it can be a clown show at times. If they get in my personal space or forget gs etiquette, i'll remind them and let them know how I feel in no uncertain terms. Luckily that does not happen very often.
Here is a story...
Last weekend at the sale with all the glass, as I first walked in I saw a couple there whom I'd recognized from the local flea market. Real sleazy looking white trash kind of people. I started looking at the glass on one of the 6 table fulls there. All of a sudden the lady speaks up loudly, "that whole table is sold, it's mine!" I said "oh really?, did you get a price, is it paid for yet?" She says "no, we are working that out now." I said "oh, then it's not actually yours yet your just pulling a Haitian move!"
This is a technique I've seen used many times before by the local Haitian buyers, they are the only ones I have seen do it, that is the reason I said it. They say "that is all mine" then when it comes time to pay they end up not buying the vast majority of it, if any. Anyway, she more or less ignored the comments as her fidgety crackhead looking boyfriend says nothing. I went back to looking through the other tables full of glass and didn't pay any mind to these two anymore. The people holding the sale were now busy wrapping each piece in newspaper and packing it up in 2 plastic tubs for them. Long story short, they worked for about 20 minutes wrapping these items up, the total was $165 (overheard). When it came time to pay, the couple refused to pay that amount and left without buying anything (straight Haitian move). The price was very fair for what they had. I called them a couple of bums as they were leaving. I couldn't help it. The people who were doing the wrapping and packing were po'd to say the least. They had to sit there and unwrap every single piece they had just wrapped.
The people holding the sale told me they didn't know what to think when I was saying what I said when I first arrived. After the deal fell through I explained why I said what I said and told them I was familiar with the 2 that had just left and reneged on the deal. I explained the Haitian comment and the irony of what had just happened. It was like I seen it coming. They were mad as heck at those people and they loved me by the time I was done, well they loved my money anyway, lol. That was my excitement for the week.