Nostalgia is everything that pertains to a time gone by; recent or not so recent; something that elicits memories, good or not so good. Anything that engenders any sort of longing; could be yearning for the freedom of our childhood, or could be wanting to listen to a particular kind of music we would be glued to during our teens, or simply visiting old memory lanes (including your favourite chai ki dukaan, or your favourite movie hall), and all this in your imagination.
Memories which are fleeting, that come and go, and don’t linger around like old friends, cannot be termed “Nostalgia”. It is more like a memory-flash, and may or may not make you feel anything at all. You might never think of it again. However, when one is truly nostalgic, one might even forget the present completely and be transported back to the past, where they can actually smell the air, see the sights, listen to the sounds that they had once been a part of and experienced. The past becomes reality, and the present, turns into an aberration. How convenient and wonderful, isn’t it? No wonder, nostalgic memories of the positive kind should always be welcomed.