Lots of teams listed for simplicity of writing the poll.

My argument would be for the Calgary Flames. They traded a bunch of draft picks for Travis Hamonic with the expectation that a strong top line, a possession-dominant second line, and an elite defense group would propel them into being a cup contender. They have been unable to capture the consistent success many of us believed was possible. Despite having a great season out of Mike Smith, the Flames are poised four points out of a playoff spot with no games in hand, and in many cases, games owed. By the end of the week, it is entirely possible they are eight points out of a playoff spot. Meanwhile, the New York Islanders currently are in possession of the Flames' first round pick for this season, and their next two second round picks. Although the Flames have a deep prospect pool defensively, they lack the cap space to add proven talent to the roster without stripping away other NHL talent or restricting them for future years.

Gaudreau mentioned a three-year window over the summer where many of the guys are the team become free agents. I for one believe year one (of what really is a two-year window) has been wasted.

My runners up:
2nd Place: Arizona Coyotes
3rd Place: Ottawa Senators
4th Place: Edmonton Oilers
5th Place: Pittsburgh Penguins

My most disappointing team this is year is Pittsburgh, they're out of a playoff start and I was expecting them to be the top of the metro, lack of chemistry and disappointing seasons from, Malkin, Letang and Crosby are reasons too. The only one having a better season this year than last is Maatta, last season was a bummer for him. The injury bug that's been here since we won the stanley cup in 2009, struck once again and it's just starting.

Montreal also has been disappointing too, I thought they were going to make the playoffs and not be in contention for the lottery, bad GM, lack of centers, and overall just a bad team. Everyone but Gally has been awful this year. It's a shame. The injury bug likes them also.

Overall, lots are disappointing as well, Oilers, Coyotes, Flames and Senators were disappointing. However I don't following these teams and my dad who's a sens fan doesn't know the problem with the sens.

Personally, I expected Montreal to crash this year, and while I didn’t predict it I’m not surprised Pittsburgh and Ottawa are struggling. I do think the Pens will get into the playoffs, and that the Sens will heat up (but will still miss). My big surprises are:
1. Edmonton: this one is huge, while the Oilers do have lots of notable weaknesses nobody expected this, however, they are beginning to heat up so there is still a chance they sneak into the playoffs.
2. Arizona: I did not think they would be a playoff team, but with all their young talent and new players I expected they would contend.
3. Buffalo: going into the season I though the Leafs would have serious competition from the Sabres, clearly I was wrong as the Sabres roster has been mismanaged yet again.

Eh? Lots did however my optimism failed me. I expected them to be third in the Atlantic however I'm just shocked. I didn't expect them to be lottery contenders. The management must go asap. Rebuild time!

While, being a Habs fan, this season is really disappointing. The was a lot of doubt going this season for MTL.

EDM however had expectations through the roof! And to see where they are now is not good seeing that things will only get harder for them to improve with McJesus’s contract kicking in next year.

Two years, the Pens were a questionable playoff team mid way through the season and beyond. They got better, and had great playoff wins the Cup.
Last year that were consistently good. I'm wondering if we're seeing the demise of the Pens to a mediocre team. After there top 6 six players, they seem very ordinary. Not just good enough now.
Calgary sure has spend a lot of money of their name defence....with poor overall results.
Edmonton is showing offensive depth isn't present. And missing an NHL goalie when he's injured (Talbot), is just disastrous.
Sens, I thought they would be battling for second in the Atlantic, now battling for 2nd lottery pick. ??????

Montreal is a disappointment, but I think Habs fans started seeing the writing on the wall with that disastrous off season. We didn't expect this level of performance, but 5+ years without addressing the team's biggest need, poor development and using players out of position or in roles that their performance doesn't merit, was going to have an impact eventually.
The self orchestrated mass exodus of puck moving Dmen added a second major flaw to the roster.

That said, I'm giving it to the Oilers. If you add McDavid to a slew of top drafted prospects and squander his ELC like they have, that's a huge disappointment.