No, this is exactly how one should necromance an old thread: with a thoughtful, well-written post that significantly contributes to the topic of the thread.
(For reference to Mike and Lucy's early history, it's worth rereading "The First Meeting", "First Interaction" and "Development of Friendship" in the extras section, followed by "Left Behind" and "Unfulfilled Fantasy" in the main archives.)
Let's go back to the start, shall we? In preschool, Lucy didn't fit in with any of the other kids. She never wanted to do any girl stuff, yet the guys rejected her because she wasn't a boy. So when Lucy first met Mike, she instigated a rivalry with him because he was a boy and she wanted to prove she was better than him. Yet at the same time, Lucy liked Mike because he didn't expect her to be all girly. Mike was the only one back then who accepted Lucy, and that was the beginning of Lucy clinging to him and following him around. For a long time, Mike was the only guy friend that Lucy ever considered. And all during this time, she was competitive with him, punching him and calling him a jerkface and trying to beat him at games.
Then came third grade, where Mike virtually ignored Lucy in favour of Sandy. It's hard to fault him for spending so much time with Sandy though, since she was actually nice
to him in a way Lucy never was. Despite this, Lucy still hung around nearby, and Sandy often invited her to join in their activities. However, it always ended up that Mike focused his attention on Sandy, so that Lucy was left all alone once again. That was partially assuaged by finding the egg Yashy was born from. Yet once Sandy moved away, Lucy went right back to Mike. And Mike let her, since he felt kind of bad that he'd ignored Lucy the whole year.
At first Mike and Sandy wrote to each other frequently, but as time passed, the letters became less frequent. Lucy was always around though, and Mike grew closer to her and began to develop feelings for her. In seventh grade, Mike first kissed Lucy, but she pushed
him away because she wasn't ready to get close to anyone romantically just yet. Then at the end of "Confrontation", Lucy kissed Mike, but told him not to think more of it. In a way, Lucy was toying with Mike's feelings, giving him hope for a relationship, and yet keeping her distance from him. And when Lucy did finally confess her love to Mike? It was too late, because he'd already committed to Sandy, a fact which Lucy knew perfectly well. And in point of fact, it was Lucy
who got Mike to realize Sandy was his girlfriend. So when she confessed to Mike, really, what could he do?
That was when Mike began getting tired of Lucy's behaviour, of her clinging and dependence and yet pushing him away all the time. Then later when Abbey talked about bullying, Mike realized (panels 2 and 3)
that was what Lucy had been doing to him all along, with the abuse she'd been heaping on him for years. And he'd borne it all along because he was the only one Lucy chose to be close to. All this time, he'd been Lucy's pillar of support/punching bag. That was the point where he decided to ignore/avoid Lucy as much as possible, so as to get away from her and force her to become less dependent on him. Note how Mike got annoyed when he thought Lucy was trying to cling
to Augustus instead, and then again when Lucy clung to him
once more in her delirium.
Now Mike is definitely a quieter guy and not one to share his problems with other people (and especially not Lucy). The few times we see Mike actually confiding in someone are with Sandy
. Mike didn't really want to burden his long-distance girlfriend with his problems, but Sandy was genuinely concerned for Mike, and she helped convince him that he shouldn't be around Lucy if she was hitting him so much. Abbey's rant about bullying was just the final catalyst for that decision.
So there it is: Mike has now broken ties with Lucy, because she never was that much of a friend to him. He was always supporting her, but what did she really give him in return as a true friend? Friendship is all about giving and taking, but in this case it was Lucy doing all the taking. Lucy basically abused their friendship, and Mike finally had enough of that. He pushed her away for once, and who can blame him for that? His actions are entirely understandable in context, since Lucy was always alternately punching him and clinging to him emotionally. Such abuse should never be acceptable, which is why I tend to favour Mike over Lucy on this whole thing. Both of them have lessons to learn, but Lucy more so than Mike.
Yet I do have some sympathy for Lucy; perhaps everything would
have been different from the start if she'd been born a boy. At least then she would've been accepted by the other boys, and wouldn't have become so dependent on one single person. In retrospect, it's kinda too bad that Lucy's mom reinforced the gender divide by giving her a pink bow to wear.
And it could be argued that Paulo's right and Mike is a total pansy, just for not having stood up to Lucy even once during all this time. Indeed, if Mike had told Lucy from the start how she was hurting him and asked her to stop, then they might have been better friends afterwards. And with a solid friendship as a base, they might even now be in a relationship. Of course, that didn't turn out to be the case; even Mike admitted he was a total pushover back then.
Yet even someone as laid-back as Mike has a boiling point, and in "December" he reached it. He ran out of patience with Lucy and outright told her he hated her. That was the one thing guaranteed to make her leave him alone. And in truth, Mike has cause to be bitter towards Lucy. He can hold a grudge for a long time too, so I think it will be quite a while before the two reconcile again. They might be ready to be friends again a year from now, presuming that they've both matured and learned their lessons during that time.
Oh man, this got long. Definitely not apologizing for that though. Not giving you a TL;DR either, so read the whole thing or skip it.