I'm replaying from the start (to refresh my memory & relive the amazing moments) so I haven't got to the new stuff yet.
But looking at it from MC's point of view I can see giving Elaine a chance.
When he first arrived at the house, he was angry with Becca, not inclined to stay or to give her a chance.
He was only there because he had no other choice & seriously considering suicide as a viable alternative.
Sandra asked him to be nice & it worked out very well.
Fiona didn't make the best first impression either, but he again gives her a chance & again it is working out well.
So the pattern has been set.
Bad initial impression, but don't fight fire with fire. Take a step back, be open & see how good things can become...