Pretty sure my MIL genuinely likes me the most out of all her actual kids and in-laws.  I didn't really go out of my way to win approval or to prove a point, I just show up and calmly offer common-sense help when the hurricanes of life arrive.  She definitely works hard to please her children, though, and doesn't miss a chance to do her best for them.  Maybe it's because I don't try to make her earn my approval.

Early in my marriage I did approach them directly and ask them to help me in directing my wife's job frustration in a more positive way instead of (to be fair, only occasionally, at least when I was present) throwing fuel on the fire.  I didn't beg or plead, I simply asked them to help promote a more positive perspective on taking personal responsibility and control of feelings.  It was up to them to comply or respond and they generally have done their best, at least when I am around.

My inlaws are more or less retired and they are not farmers, and we don't work together. We do live in the same town, more or less, and my wife emails and texts her mother daily and sees her both weekend days and most summer days.