Last year I got a bit overloaded between work and being the DM of my D&D games. So I arranged myself with players from my two large campaigns that someone else would take over, at least temporarily, as a DM, and I would switch to the less work-intensive job of a player. That worked out fine, and in one of the campaigns I am already back to being the DM. But I think that in the other campaign I made a bad choice of character class when choosing a bard.

Now I don't want to give you the impression that the bard is a bad class. I actually played a "college of swords" bard in a different campaign that was lots of fun. But this bard is "college of lore", and in this particular campaign he really doesn't work out all that well. In every fight I can do something really powerful once: Turn an enemy into a sheep, turn a friend into a Tyrannosaurus Rex, give advantage to all my friends, disable several enemies at once, heal 20d6 over 10 turns, and lots of similar things that don't usually involve damage. If I fail, I can try something else next turn. But if I succeed, I am basically done for the rest of the fight: I need to keep up concentration on that spell, otherwise it expires. Which means not casting another concentration spell, and trying not to get hit. So I end up casting my basic cantrip, vicious mockery, but that also is more of a support spell and doesn't deal much damage. The overall effect is that if a combat takes more than a couple of turns, I usually end up being quite bored at the end.

I think the problem is less with the bard, than with the concentration mechanic in 5th edition Dungeons & Dragons. I understand why it is in the game, to prevent spellcasters of having active several powerful spell effects at once. The famous invisible flying wizard of previous editions is no more, and that is good. But in terms of players getting to do something fun at every turn of combat, concentration really gets in the way badly. It works okay-ish for hybrid classes that can cast spells and fight, e.g. the paladin. But even then you basically need the war caster feat to not permanently lose concentration. My paladin is using his spell slots for divine smites rather than for casting concentration spells. The overall effect is that players drift towards spells without concentration, which also tend to be more damage-dealing spells. That makes the game flashier, and a lot of people enjoy that. But somehow I feel that this edition is losing a part of the charm of previous versions of Dungeons & Dragons because of it.