Why do some families dislike a spouse without getting to know them, and how can you help your partner feel accepted regardless?

We swapped bodies for a day. What is the first annoying habit of mine you would try to fix?
I just smoked a whole bowl of marijuana on my break at work. Is this okay? Will my boss care?
How should a professional decide when it is time to leave a comfortable, established routine to pursue a completely unexplored path?