So, I've seen many fans say this is an episode that serves Rarity right for taking advantage of Spike for so long, portrays her as an overly creepy stalker, etc., but I can't bring myself to agree with any of that.
The episode opens with Spike not only barely paying any attention to her at the beginning, but also not responding to her invitation. Though it's understandable and even acceptable that Spike had a new friend that he wanted to meet, he didn't actually tell her until she asked. How would you feel if you invited someone to do something with you, and instead of telling you they're busy, they don't say anything at all? Although I do understand that Spike might have been too preoccupied to tell her or respond to the invitation, but still.
Though I don't entirely disagree there were some characterization problems. Rather than doing a dramatic apology before even asking what happened, and guilt tripping him to spend time with her in the middle of the night via looking disappointed, even if said disappointment was legit...well, let's just say both those things could have been handled differently. Maybe she could have asked what happened BEFORE doing a dramatic apology, and even if she legit felt bad in the middle of the night about Spike not being able to spend time with her the following day, reschedule or find a day that does work.
Though I admittedly liked the resolve of Rarity learning that it's ok for Spike to have another friend and even going as far as to try to fix the mess she made of his and Gabby's friendship.
Although I can understand some of the heat this episode gets, that doesn't mean I agree with it entirely. I think we've all been guilty of overreacting, making assumptions without proof, going to certain extremes, etc. At some point or another in misc. Situations.
I'm afraid I also can't agree with the claim that she takes advantage of him all the time. He chooses to help her, and there are select moments when she stands up for him and/or shows appreciation, even if said moments are arguably select.
Overall, despite Rarity going to some unnecessary extremes, she wasn't the "creepy obsessive stalker" as many haters claim. Also, Jim Miller has even tweeted that Spike is likely between 16-22 in pony years, but we'll save that debate in regards to the ship itself as a separate topic.
Certainly not without its faults, but also not the horrible train wreck some try to claim it is either.