I noticed a theme recently, which is that as of late, I've been late to just about everything. Which leads to...
Lesson #3: Take the amount of time you think it'll take you to go somewhere, and add 10-15 minutes. You'll still probably be late, just less late, more in an adorable 'she's a bit irresponsible, God love her,' and less of a 'rude New Yorker, doesn't care about other people's time' way. On second thought, maybe it's better to fall into the latter category?
Either way, just assume that it'll take you longer than you think to get just about anywhere. I do realize that there have been various service interruptions to the subway, but even just walking I usually go the wrong direction a couple blocks here & there, which adds up. Before NYC, I kind of prided myself on being on time (this is quite tame of me, I realize) - but I've found that being late adds so much stress to life! The frantic stride, the flushed cheeks, the anger that starts brewing...these are not my favorite things.
Basically, there needs to be more than 24 hours in a day to accomplish all the things I'd like to do, and not be consistently late for each. Such is life!