Specific food items from the countries which deliver loads of expats can-at a price-and usually only in those shops in areas with a higher concentration of those-in the well known hypermarket chains that are everywhere in TH-used to be Tesco (UK), Carrefour (FR, first to give up) and BigC (started also as joint venture with FR/Casino-since then took over all Carrfr and is now all Thai) and supermarkets TOPs-originally run/set up by the dutch (Ahold)-and since also sold off to Thai., the Belgians (Food Lion, by delHaize) very soon gave up and sold to TOPs. Plus that-like also about anywhere in Europe in ethnic areas-there will be ´local food shops´ catering to them. Plus that the last yrs online ordering has taken a big take-off. MOst expats are married or have relation with Thai ladies and instruct them how to make their favorite foods, with what there is locally.
Clothes: again: TH abounds with very cheap tailors-make to demand. I am quite the opposite-my small size is here in EUR often hard to get and thus TH is for me a great place to buy. But the nasty thing is that textiles are not properly labelled, as they are in EUR so you can never be sure if its like 100% cotton/silk or not. There are also 1000s of stands with 2nd hand clothing imported from western countries and with proper labels-they say these were meant as aid for Cambodia and they could get more of it by selling to the Thai.......But this makes shopping rather an adventure-you will never know what there is there/that time etc.-time waster