It depends on the vendor, even if I had 300 PM's to get through, a little thank you is still appreciated as I know it has arrived safely and everything is up to expectations. Feedback is the only way for a vendor to know what his/her customers truly want which is why I like hearing it, even the smallest little nags or thoughts are appreciated since it is usually the small things which make the biggest difference.One person recently let me know the laws in their country and it meant that instead of sending 100 pills in 1 package which would be seized, sending 50 is perfectly safe so dividing up packages would ensure even if opened it will be sent on to the customer. It's little things like that which make the difference between a package arriving or not in some circumstances and as we all know, that 1 customer can make a big difference to rating.