coincidence?

So last Saturday some of family came to town to kind of celebrate my birthday, which is on Wednesday. We ended up having a late breakfast or brunch at the Nova Cafe, and my little sister had a smoothie and was just drinking it like there was no tomorrow. After awhile I look at her and say, don't drink of it before your food gets here, and before I could even finish my sentence the waitress walks up with our food. My sister just starts laughing like crazy and tells me that I have to use that for my Mythologies class. This just makes me wonder if coincidences have more of a reason for happening than just randomly working out that way.