While most of these are a good rule of thumb, I disagree with ‘Always Happy to Help.’ > ‘No Problem.’

‘I’m Always Happy to Help’ is a fine response, if you’re actually willing to make your time available for the recipient at the drop of a hat. Sometimes that’s called for, but I would only reserve it for a few very specific circumstances. I also don’t see an issue with saying ‘no problem’ most of the time. There are situations where something a little more formal is called for, but 90% of the time ‘no problem’ should work imho.