From my analysis of halo reach's multiplayer, I determined that the frustration and rage behind it came from a combination of little annoyance's, that we as dedicated halo fans didn't experience in previous Halo titles, that all added up to make the multiplayer equation equal to a less enjoyable experience than previous title's multiplayer.

One important irritation was armor abilities and there "ability" to slow down the pace of the game and increase the overall time of battles, decreasing the sense of satisfaction as achieving success in a lot of battles required a greater amount of work than in previous titles. Sprint and evade allowed you to run away from battles easily that would have otherwise been lost in previous titles. Armor lock stops the action for a whole 3 or 4 seconds and sometimes allows others to come in and clean you up thus not giving you the kill you would have earned in previous titles. Active Camo slows the pace of the game and irritates your radar requiring you to search around every corner that you used to not have to as much and it means players are rewarded for not moving which slows the pace of the matches. This rarely occurred in previous titles except during highly competitive matches where the drama of the scoreboard was on the line and brought intensity and immersion. Jet Pack gave a huge advantage in not only height but also gave players access to angles that used to be unattainable in previous halo titles thus causing frustration. So with every armor ability adding together as every player spawns with them, the pace and sense of reward slows down immensely in all battles causing the players on the receiving end of armor abilities to have to work about twice as hard and twice as long then they ever had to in previous halo titles just to succeed.

When you have to work so hard for your kills, the effort required immensely outweighs the reward and this is incredibly irritating to the audience of halo players that had grown used to the time and available options of battles in the past 9 years of playing Halo. Imagine if they doubled the amount of health for players in Call of duty? can you imagine how irritating that would be for everybody who were used to shooting for a second or two to get a kill to having to put almost an entire clip into somebody or double the effort into an engagement just for the same reward? it would ruin the fun, immersion, and flow of the game that is already present.

Now back to reach, we also saw the addition of the bloom mechanic. Now I think the bloom mechanic works great for the pistol and ar as it is a great balance of the two weapons in both fun and function; however the default bloom of the marksman weapon, the dmr, was too much at launch and greatly affected people initial impressions of the game because it is also another new mechanic that affects the time and pace of battles. Because you have to slow down your reticle for the bloom to reset it gives the opponents the opportunity to make there escape if they are armed with sprint,evade, or jetpack, or the opportunity to spam shots and get lucky because of the bloom mechanics. Now here is another problem present in bloom, luck. Luck does not belong in halo as a game design mechanic. Halo is about balance and everyone being on an even playing field. Aim, Map and weapon control and teamwork are keys to success. Because we have to deal with the luck mechanic in the competitive/marksman weapon, this ruins the skill of aim that was present in all other halo titles and as it is the primary way of interacting with the game it is extremely important for it to balanced and work correctly for a satisfying experience. Thus bloom is another addition to the game that increases the time of battles and also brings luck into the Halo multiplayer equation that was never apart of previous equations in the Halo video game series over the past 9 years.

As you can see because of the equation being unbalanced compared to previous halo titles due to the increased time of battles from the addition of armor abilities and bloom, and the addition of luck into aiming, Halo reach multiplayer came to be more frustrating and "rage filled" than it was enjoyable, and thus less enjoyable for myself and others than previous halo multiplayer iterations.

Hope this helped you maybe see why reach multiplayer was a less enjoyable experience for you :D as for firefight I never really touched it as the lag was too unplayable for me to enjoy it :/