@grantheaslip: For restaurant tips I believe the rule is 10% of what your total bill. So if my bill is $40 I normally leave $5 bucks. I sometimes leave a few extra dollars if my service was great. The only time I don't tip is if we have a group of 5 or more people. They normally they include the tip in the final bill.
@mosespippy: I was thinking the same but DLC and system updates shouldn't be using 56 GB's. Borderlands is probably the one game that gets patched and has the most DLC. If anything that should be the culprit.