Unspoken rules?

What could it be? Everyone has different values and perceptions, but... If there are three new flowers displayed in the market? I buy only one. If time passes and they're still there, I buy more. Some of my friends... They put various things on the market, and people buy them all immediately. Even if they put them out after some time, they buy them all. I want various friends to buy them... It's frustrating. On the farm, I pick only the flowers I want, multiple times. It's also frustrating that they use tags to recover them for the next person. If it happens again, I'll just remove them, and they become quiet... Sorry for venting.