I'm not a real MIL, NanaNina, because neither of my boys is married; but one is engaged and the other has a four-month old baby with his GF, so I say I have DIL-ishs.
But you're right, most people here see only the DIL's point of view, and to be fair twenty-odd years ago so would I. I'm not all that close to my MIL, and some things she did when my boys were little upset me, but as the years have passed I've come to realise that "whatever it was" wasn't particularly serious and had only the importance I chose to give it. She's not malicious or ill-intentioned, she just has different priorities from me. I know I'm not the DIL she dreamed of, but hey, I'm what she's got.
Of course, some women are genuinely and quite deliberately unpleasant towards their MILs/DILs/other women generally, but I think the vast majority of upsets are caused through misunderstandings.
And once mums become MILs - and even mothers of daughters do that, though they're less often mentioned here, for obvious reasons - they can start to understand the other side of the coin. Maybe you have to live it to have some empathy?
I'm still very new to this, but I try to have good relationships with my DIL-ishs. I think I'm doing OK with the mother of my DGS, but my other DIL-ish is a sensitive soul and sometimes I worry that I may inadvertantly have upset her; however, I adopt the attitude that if I do upset her, she or my DS should tell me so and not expect me to be bloody psychic! And I think more folk could do with adopting that attitude too; it seems to me that too many mums fizz and fume in private, but don't actually tackle the issue with their MILs, who are left in the dark and so repeat the upsetting behaviour.
You (generalised you, not a personal one) see your DH/DP as a grown man and expect him to take on responsibilities accordingly; your MIL still remembers the wee boy who wet himself in terror on his first day at nursery. It'll be you one day; cut her some slack, eh?
dons fireproof clothing and retreats to a great distance