Mine wasn't a sex analogy
Staying on topic. I think the writing of ME3 is the one that feels the realest. Not the smartest, the dumbest or the most interesting but the one that feels the most real.
Why would ashley/kaiden consider betraying shepard? For years they thought they were dead, only to learn they were alive and under the service of terrorists, why should they trust him or her?
The reapers are the result of a exceptional A.I the whole time. Underwhelming but understandable, you can't argue with something that's insane and they're no less scary anyway.
The geth and the Quarians can't put their grudge aside for even the end of the world without shepard's help. We feel this in country's now, war between the two is all they know, peace is just as alien to them as the reapers.
The ending was a let down, but not all stories have a happy ending, not all battles are won with a golden bullet, sometimes bittersweet is the best we have.
Its why I can appreciate me3 now, it can take a very weird and alien universe and bring it down to a human level, a real level.