I had an experience like this several years ago, after a very intense period of my life, whilst commuting home from work. A state of expanded awareness gradually came over me, I began to sense the Unity of everything - people and objects seemed to glow with bright colours and I was filled with the most ecstatic joy I have ever felt. For some reason, people on the train, in the street and in the supermarket I visited on the way home seemed to be drawn to me: as they approached I could sense their needs, hopes, sadnesses and dreams, and did my best to reach them in some way.
In the supermarket I realised I was in such an altered state of mind it was impossible to think normally or make choices, until I realised that the objects I needed to buy were actually glowing brightly on the shelves, so I just picked up everything that was "shining". Later, when I returned to "normal", I checked out my purchases and had in fact correctly chosen everything that was on my list. I met a confused old lady in the shop - possibly suffering from Alzheimer's - who was struggling to remember what she wanted to buy.
Normally, I would have avoided her, but on that day I gently spoke to her, calmed her down, helped her make her purchases and guided her to the checkout. Outside the supermarket, I approached the homeless people who hung out there begging for money, and spent some time listening to their stories and for the first time really appreciated how they had suffered.
On the walk home from the shop I was hit by revelation after revelation about the true nature and purpose of life and the importance of every single human being, no matter how far they had strayed from their true Self. I could sense the presence of alternate worlds, in juxtaposition with our own but normally veiled from our perceptions. After I got home, I lay down and let the continuing stream of higher consciousness wash over me for the next few hours. I phoned a few good friends and shared some of what I was experiencing with them.
This altered state lasted for the next two or three days, gradually fading until my consciousness returned to normal, but I was forever changed by the experience. I don't remember everything from that time, but a surprising number of the "cosmic" revelations stayed with me to this day.
In case you're wondering, no, I had not taken any hallucinogenic substances! However I had been running on adrenaline and very little sleep for several weeks due to a very heavy and demanding period both at work and home.
I've not experienced anything this powerful since, though I've come close on a few other occasions. I still remember the overwhelming joy and the expanded perceptions - perhaps this is what true enlightenment truly feels like? No wonder people such as the Dali Lama or Nelson Mandela always seem so happy, despite the hardships they have endured. It also explains why most spiritual traditions insist on the importance of spending many years of discipline and training from their disciples. Without this training, we are simply not equipped to function at the higher level of consciousness I briefly experienced.
Part of me longs to go back to that state, but I know that I lack the discipline and wisdom to function like that for very long. My brain cells would probably burn out or short-circuit from the overload - I certainly would not be able to hold down a job and would probably be referred for a psychiatric assessment at the very least!
Still, if this is our ultimate potential as a species, then we should be doing everything in our power to get there asap! Unfortunately, we are a long, long way from this and we have a massive task in front of us, to not merely survive the coming climactic upheavals, but to ensure that every single human soul can reach this state of Nirvana!