I'll start off with the trend of giving a delivery date as soon as a shipping label is created and it doesn't take into account the collection or delivery location. I've got a parcel coming from the Netherlands at the moment, label created Monday, parcel collected but they thought it would arrive yesterday, it didn't. Then UPS didn't update the delivery estimate or give any updates.
Also, the UPS website is a massive pile of *****, so slow and clunky and I shouldn't have to create an account to use it. Imagine a website that says you can set certain information on one screen (door code) and then you can't do it.