Recently I have noticed some supermarkets are not bothering with the 25 and 50 satang coins if paying by cash. If I have loose change and do not have the satang they are not bothered and roll the total bill down. If I give them an extra 1 baht they do not give any satang back in change. It is such a small amount surely it would be better for the government to take them out of circulation.
As a last resort one time I took out the draw of a cupboard and taped it to the underside within an envelope. Anyone snooping will tend to just look inside the draw not underneath. I think I saw it on a movie once.
The only legal reason for flashing your lights in the UK is for a warning of your presence although its widely used for other reasons, like you mentioned. Rule 110. Flashing headlights. Only flash your headlights to let other road users know that you are there. Do not flash your headlights to convey any other message or intimidate other road users.
When younger my mates pull line was " Will you have a bath with me? I will take the tap end" This would certainly break the ice with a girl and was quite successful.
Even if they brought in proper driver training, enforcement etc tomorrow, it will take a couple of generations before they click on to how dangerous there driving is. They have no observation, consideration or anticipation when it comes to driving.