I am currently in that zone. You can't sleep, you can't eat, you just wait.. regretting things you didn't get done during your trip and dreading the many hours still left to spend, just waiting in this limbo of irrelevance to anyone's lives that I call the Twilight Zone.
You try to fill it with an endless landscape of meaningless tasks. I am sure that if a study were done, more books would get read during this time than any other. I now have 10 hours to while away, 6 in the hotel, until I get thrown out (officially called checkout) and then 4 in the interim period in which I will idle away ambling around the shops here and in the airport. If I were to scrutinise my trip, the purpose of my visit was over after the first day here - it usually is. The rest of the time has been filled with social visits and meaningless banter, whiling away the time until I leave.
Regrets, always. I heard it once sad that you only ever regret the things you didn't get done, and have always found it to be true. As actions are far harder than ideas and 'stated' intentions they take much more energy to get done, and often a lot more courage. This hiatus to ponder allows me to reflect upon this very thing. Actions are the only thing that takes our ideas and converts them into reality.
Indeed, I have heard so many 'ideas' and 'intentions' over the past few days that I am completely full of them and am simply able to regard them as no more than hot air. Intentions and ideas unfulfilled lead only to regret, missed opportunities and inaction.
Inaction, albeit sometimes not conscious, is in itself 'action'. it is failure to ensure things are done, failure to deliver, failure to keep promises, excuses given etc etc. But however it is dressed, it ends up the same 'what if?' and usually ends up in regret. However this regret is meaningless because participation was taken. Action was in fact taken, even though that action was the action of non-action.
Presently I am regretting not delivering some of the messages I tried to effectively. Regretting not seeing some of the people I hoped to do. Regretting not doing some of the things I wanted to, such as taking the last day here to see my son whom I haven't seen for over 2 years. Regret leads to self-criticism and dissatisfaction.
Given the current climate generally, many people now out of work will regret all the things they never got done during that time. However if you look at it pragmatically, you never would have done the things you yearn for having done because by your 'active inaction' your decision was already made. Therefore best to stop regretting and let go if the idea that you would have done 'if only things had been different' - you never would have done. Simply accepting this and letting it go is the best remedy for regret.
Regret is never action, it is always inaction, but taken as a positive, it is a decision made and acted upon. Regrets are usually only reflected on in twilight zones such as these, and approaching death, where you have the slack in life to enable you to see how pathetic it all is.