This weekend I was made to think about this a bit when I met up with some friends in Luton. We were planning a children's Christian sailing holiday that we have run at Easter for 66 years (no, we haven't been personally involved that long but the cruise is that old). We are a disparate group of people who only seem to have faith and sailing in common but somehow we travel well together. There is banter and laughter but also serious work and discussions. And on top of that there are long term friendships of great depth. I didn't choose these particular folks to journey with - they all arrived on the cruise from a variety of directions unconnected to me - but I am happy that we walk the road together, supporting, helping and encouraging each other.
The second instance was flying back up from Luton with the orange airline. Lindsay and I had been forced by circumstance to book our return flight separately which meant that she was allocated a seat in row 8 whilst I languished in 24C. On the trip down I slept half the way but at least we were sat together. Yesterday we couldn't even see each other and it was not the same. It's like when you are hillwalking and your companion disappears over the brow of a hill - suddenly the journey is less fun. Part of you knows they are still there but there is a sense of having to carry on alone that is less pleasant.
Sometimes we take these people for granted but apparently that is the biggest regret people have at the end of their lives. Check who you have in the metaphorical seats next to you on your journey and consider what you can do to relate better to them (assuming of course you are already on the right bus, heading in the right direction with the right companions - if not then those considerations should probably take priority).