Are shop assistants globally trained to piss me off?

In developing countries they are constantly two steps behind me, turning corners with me in tandem least I try to shove that toilet roll into my bag or make a run for it with my litre of mineral water (cue inner rantings of "Do you really think I would steal your stuff when I could buy this entire shop on an hour's wage rah rah imperialist rah?")

In the UK I have to practically set my head on fire to get them to either deign or be bothered to notice my irksome presence and some have mastered the art of serving me and giving me change without interrupting their conversation with their colleague ("You aren't blind are you? So you are, in that case, able to figure out the total or read the till by yourself.")

In Japan, the moment a finger barely touches a garment, the assistant rushes over to tell me that I can try it on if I so wish. Slide another hanger and, yes, that garment is also available for a trip to the changing room. Pause for five seconds to look at something and I will be given the run down on how I could wear it and how good it would look on me. If, against my better judgement, I get carried along with the clerk's enthusiasm(i.e. glimmer of commission on the horizon) and head for the changing room I will be given a large white hood to cover my face to prevent make up getting on the clothes (even if I'm not wearing any as they don't believe me!) Then, after approximately twenty seconds, I will panic as an alarmingly close voice is asking me how I am getting on and I'm unsure how to reply as I currently resemble naked bee-keeper.

If I can stand it thus far and make a purchase I will be guided through the transaction in great detail and grand manner "That comes to 6995 yen. You've given me 7000 yen and your points card. Here is your 5 yen change but please wait a moment while I add your points. Thank you for waiting. Here is your points card. Please wait again while I wrap your purchases. Here is your purchase which I will hand over after I have accompanied you to the shop entrance. Here is your purchase. Thank you for your custom and do come again"

In the Philippines, despite my protestations, they make me try on a child's T shirt as they are quite sure that they don't have any larger sizes and they are know it will fit. Obviously, it barely covers my chest as hooting with laughter, they suddenly find my size. LL. Munter size. I make a joke that I've become fat as I've gone from M in the UK to L in Japan to LL in the Philippines. They say "You're not fat, M'aam. You're chubby."