In my experience, yes.
My boyfriend is a Pisces, and his habitual actions can be fairly daunting. He wants all things done his way or not done at all. He expects everything to go accordingly. Otherwise, he'll throw a tantrum and snap at everyone.
Aside from him being neat, as in appearance or performance; he's very precise. For example, he does his laundry every other day, along with organizing all of his items in their specific places. He hides things, for some reason. Which is amusing how he tends to loose things anyway. But sometimes I wonder if he considers me that way.
He he this ideal idea for a relationship. Our relationship, anyway. If we get into an argument, and he doesn't want to hear what I have to say, the conversation is ended.
My conclusion is that since they're an emotional zodiac sign, they get emotionally involved very easily. I've read that Pisces feel happiness and sadness more than people can possibly understand. For that reason, I believe they tend to go overboard. They may not even realize how this affects others.
But I relate this to various control and trust issues.
Observation, while I've been dating and residing with a Pisces for 3 months now.