If they ask if you prefer "indica or sativa," feel free to ignore anything that person has to say on the subject. It isn't necessarily their fault, but they are severely misinformed, so it isn't likely anything they say has an actual basis in reality.
I think I read about a study that did genetic analysis on a lot of cannabis "strains," and there wasn't much correlation between a strain being labeled indica or sativa and its genetic make-up.
That being said, different strains of flower do seem to give me somewhat different effects. It could be all in my head, but I don't think so. All vape pens and edibles I've tried feel pretty much the same though.
Indica or sativa is still generally the best way to narrow down what someone wants. And the majority of indicas are gonna be heavier, and a majority of sativas more heady and energetic. That said, there’s lots that don’t. And for places like where I am, without terpene testing for flower, apart from guessing off of smell, indica or sativa is what we got.
It also goes both ways. Some people don’t want to hear new info or try something different. I can’t try to explain that this particular indica is very heady, but if they want their Indica they can get it.
Indica and sativa are literally meaningless, other then they are terms that nonscientific growers came up with to describe the two basic phenotypes they observed when growing. This has now turned into marketing nonsense about the "type" of high experience. There are other psychoactive compounds contained in cannabis and some interact with each other. None of this has to do with the plants' general appearance.