I followed advice by Mark Manson in his book The Subtle Art of… By giving 0 Fcuks to the delay caused by someone. Focussing on myself during the waiting period makes everything easy. If someone arrives 30 mins late, I don't spend 30 minutes extra if I have another engagement. If they are late and expect me to adjust then sorry. My time is important to me and hence i chose to focus on my chores. I had a friend who used to be late by 1.5 hours. I reduced my meetings with her. If she really wanted to meet I would give her a time frame. Come home between 2–4 and around 4:15 i will leave for my next engagement or i will take a nap after 4. This way she knew my life didn't revolve around her.