Similar to what Donkey said,
Corcovado wrote:
I think your mom wants you to be well mannered because you're her son and she wants to know she did a good job bringing you up to be a polite young man....
In Australia we don't tip for deliveries. But if its the custom in the US, make a habit of tipping, offering visitors a drink (water, coffee, beer or whatever) etc etc. Its all about manners.
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I just dropped in to see what condition my condition was in.
Strewth!