I have been to Thailand five times for vacations of 2-3 weeks. I agree that there are a lot of scammers, but there are also some very nice, sincere and honest people, so while being cautious, we also need to be careful of stereotypes an open to human honesty and kindness.
Two years ago I was in Bangkok and I had lunch and a few beers at a trendy roadside restaurant in the downtown area. I paid the bill in cash, and when the change came back I added to it to leave what I thought was a decent tip, and then got up and left on foot.
A few minutes later as I was continuing on foot up a main road, a young waitress and waiter from the restaurant came running and shouting after me with cash in hand. They had run about 500 meters, and they gave me all of the cash I had left and explained that I had left a 1000 baht note by mistake, when I thought I had left a 100 baht note.
I thanked them profusely but I must admit I was somewhat startled by the incident so I didn’t think to give them both a tip from the cash they returned to me. So these two very honest young people wound up with no tip at all. I was leaving the next morning so I did not return to properly acknowledge their honesty, to my continuing regret. This is an event that will stick with me, and just something to be aware of: where there is bad there is often good, and vice versa. Kudos to those two young people.