I’m on time at the wrong location
God I hate when that happens.
Re: just the appt stuff - I rely heavily on my phone's calendar. Years ago, I adopted the mindset of "if it's not in the calendar, it doesn't exist", so any time I need to make a followup appt, I make sure to stop at the front desk with my phone out and do not leave until I have the date, time, and location marked in the calendar. It takes a bit of upfront effort to get the habit going, but it's been hugely beneficial for me and my family overall.
Before smart phones, I would have been the guy carrying a full planner everywhere I go.