Loy Krathong is widely celebrated throughout Thailand, where Krathongs (a small decorated basket generally made out of banana leaves with incense and candle lit) are set afloat. Given that the prefered mode of transportation was through the canals (think Venice) just decades ago (and still utilized in some areas), the Krathongs were offerings to the spirits that recede in the waters. And they serve the purpose of carrying woes of the year past to a watery abyss, which explains the popularity of this particular practice today.
Head out to any canal, river or practically any where with a decent body of water, you'll find most of the country congregated in pairs of couples still at that inseparable stage, groups of healthy functioning hormonal singles checking out their opposite numbers, and families with kids who haven't outgrown the hype (probably 20 more years to go). In other words, be prepared for the massive hordes of human, and to be gracious, given the high possiblity of encountering sticks and elbows as you attempt to make your wish upon the overpriced Krathong. (*Tip: Always buy the Krathong way before the actual day.)
That said, we only have one wish this Loy Krathong: No traffic congestion today. #TrafficBkk #HappyLoyKrathong