This also applies to personal time as well and I treat scheduling as a packing problem. It may sound non-intuitive at first but if someone asks me if I'm free

This also applies to personal time as well and I treat scheduling as a packing problem. It may sound non-intuitive at first but if someone asks me if I'm free for 1 hour on Saturday my answer will almost always be no, but if they ask if I'm free for 6 hours or free all day the answer may very well be yes assuming it's for something interesting. The reason is that 1-hour events like quick meetings or lunches put a hole in the calendar that prevents other 6-hour activities (e.g. hikes) from being scheduled.