True Gaming

I grew up with expansion packs being the norm.
There are very few memorable games from my childhood that didn't have expansion packs, and I think for many games DLC is the modern version of an expansion pack. Although DLC varies quite a bit.

Obviously there are good pieces of DLC and bad ones, and it can be hard to tell what's what. Day 1 DLC can be a big offender, but I do remember the days where games had content in them that wasn't finished.
Baldur's Gate 2 has a mod called Unfinished Business that modders finished up the content, and there is the famous Ascension mod that rewrites much of the ending of the expansion, the funny thing with this mod is that the creator was David Gaider of Bioware, one of the writers and directors of Baldur's Gate 2, due to his feelings that the expansion was unfinished he released a mod to fix his problems with it.

I don't see either thing happening in today's gaming world, that unfinished content can be finished before the game is released and then sold as DLC, being unhappy with the game's ending can be patched later on, or again sold as DLC.

My annoyances with DLC are typically pre-order bonuses, especially if they're exclusive to stores. And if they're selling very important story based content on Day 1.

I don't mind additional story content coming later, because that seems so similar to the expansion packs of years ago.

A good comparison is Mass Effect. Lair of the Shadowbroker I think is a fine DLC, it's not largely important to the plot of ME2, but it's a good side quest that is important to the character and was released about 9 months after the launch of the game.
But From Ashes in ME3 I think was terrible, it was Day 1 DLC and featured an extremely important and lore significant character locked behind an additional paywall.

That said, I do have some annoyances with DLC:
An abundance of cosmetic DLC in single player games is whatever for me, but if the game doesn't have a way to unlock other cosmetics in game, it feels like a cheap cash grab.
Pre-order DLC especially if it's store-exclusive and ESPECIALLY if it's not available for purchase later- I would like the ability to have a complete game.
Having to wait for all DLC to come out before I can feel like I'm playing a complete game. Although this isn't always new, as things like the D2 Battle Chest, Neverwinter Nights Platinum Edition or Heroes of Might and Magic 3: Complete Edition existed when I was a kid as well, where we were buying individual expansion packs as they released or we waited for the special editions.