Sorry for taking so long to put this up. Life got a little busy. Anywho, let's get to the comparisons.
Season 1: Stare Master
Season 2: Hearts and Hooves Day
Season 4: Somepony to Watch Over Me
Season 5: Brotherhooves Social
Sheesh. The selection here isn't the greatest, I'd say. None of these episodes really reach gold medal status for me. I think I'm going with this:
Brotherhooves Social > Hearts and Hooves Day > Stare Master > Somepony to Watch Over Me
Brotherhooves Social got lucky. If its competition was any stronger, it'd easily get knocked down from this spot. Heck, I'd go so far to say it would have gotten last place against the episodes of last week! That said, why is it first? Well, I thought the humor of the episode was fine. While it didn't have me in stitches, I was amused watching it and didn't really feel like cringing. Plus the ending was incredibly sweet. My biggest problem was just how Apple Bloom was at the beginning, laying it a bit toooo thick on her adoration for Applejack. It's an okay episode with a great ending, but that's about it.
So let's go to Hearts and Hooves Day. It's humor is about on par with Brotherhooves Social, at least in terms of intentionally being uncomfortable. (Plus Sweetie Belle's "Oh come on!" is always great to rewatch.) It gets second because it doesn't have any major standout moments like Brotherhooves Social's ending.