The two characters I probably played the most in World of Warcraft were a tank and a healer. That is to say that I am perfectly willing and able to understand when a certain class or style of play is required for the needs of the group, and to fill that role even if it might not be the one that brings the most personal glory or fun. Having said that, I need to add that there are limits to that approach: If playing the role that is needed is no fun at all, I may need to reconsider.

In the D&D campaign where I think I found a good balance between personal fun and usefulness for the group, I am playing a dexterity-based, dual-wielding paladin. The basic idea is that by rolling more often for attacks, it becomes more likely that I'll roll a critical hit, and can then use Divine Smite for excellent burst damage. By playing a melee combatant with not-too-bad armor class and having healing spells and abilities, I fulfill two roles that are needed for the group. But rolling lots of dice and doing sometimes spectacular take-downs with Divine Smite is also great fun for me personally.

Yesterday I played a level 8 lore bard in another campaign. My surprise move in aid of the group was to polymorph the druid into a Giant Ape, which is a far stronger animal than he can usually transform into. With one spell I basically added 157 hit points to the group's health pool and increased the group's damage output by a good amount. However polymorph is a concentration spell. That means I can't cast other concentration spells, and I need to be careful to not get hit. So that forced me into a very passive role for the rest of the combats, while the druid went ape. I was casting cantrips and the like, while he was crushing the enemies. Very efficient, and fun for the druid, but less fun for me.

Maybe I have chosen the wrong spell. I could use it differently, e.g. polymorphing an enemy into a sheep in best WoW tradition, or in casting it on myself. However both of those options are a lot less efficient: Polymorphing an enemy gives him saving throws every round to cancel the effect, and polymorphing myself means I would then be in melee combat and likely to lose concentration when getting hit. I can understand for game balance why spells that disable an enemy have been limited a lot with frequent saves and the concentration requirement; but in the end that leaves those spells somewhat underwhelming compared to other spells of the same level. And the bard gets a lot of spells like that.

In an unfortunately much less active campaign I am playing a bard of the college of swords, that is more fun to play. He has means to use his bardic inspiration on his own moves, not just to help the group. And he gets to roll more dice and be in the thick of the fight, which is more exciting. Less useful for the group maybe, more selfish, but definitively more fun to play.