Do you think it was just how they were born/their personality, or do you think it had to do with you being more experienced/less anxious/knew what to expect/etc?

I've heard a lot that your 2nd is usually easier and am curious if it has to do with pure luck or if it has to do with anything on your part. I am terrified of having a second because M was such a difficult newborn- bad sleeper/colicky, etc. The only hope I have is people keep telling me your second is usually easier.