Whenever you do good indirect deeds for someone. Mainly because some people don’t expect or normally wouldn’t have wanted things to be done in certain ways because it could get them in more shit than they were in the beginning. But sometimes doing things for the good on their behalf is a benefit.
I just wouldn’t mention it to them because it could sometimes create an issue where you may sometimes be faulted or may get into an argument about the morals of having done such thing. So by not mentioning it, it spares you from having to deal with that. I think it also has a net benefit because it doesn’t make you look like you do good things for PR reasons.
That argument annoys me so much. Each vegetable does cover all amino acids, they just don’t have them in the exact relations that our body needs. But if a vegetable has only 50% of one amino acid compared to the distribution that our body needs, then you can abso-fucking-lutely just eat double of that vegetable. Or as you say mix-and-match.
A typical Western diet includes far more protein than the body needs for maintaining itself either way.