Don't remember that. I remember the Reaper attacking the Citadel in ME1. The fight with Saren Cyborg - not so much. A mere boss fight doesn't make it memorable. I only remember Saren as antagonist because he was a memorable character. No idea who Sarevok is. There is exactly 1 fight I remember from Shadows of Amn: A Lich I whacked with my anti-magic dwarf. That's pretty much it. The hamster Bo also - and Minsc.
There's been a fight in a dungeon in Gothic 1 - it involved Orks I think. I don't remember. Some monster I guess. I remember wildlife fights more than the end fight. There was a very memorable wolf. The first wolf I encountered. A real challenge. I only remember that end dungeon tanked my computer performance-wise.
Space Marine I remember. It was a QTE fest. Not the actual fight (again, not memorable) - the final "duel" was QTE. I loathed it.
Most games I remember for their journey - not their ending. Fallout 3 was some water purifier conclusion. Peaceful iirc. Fallout Las Vegas was showdown at the Legion camp. That was proper buildup. But I think it wasn't Caesar I fought, just minion. Fallout 4 was loads of mooks and robos. Never saw Liberty Prime - picked the Brotherhood. Can't say I missed it. The Mirelurk Queens were pretty spongy already despite chucking loads of missiles at them - game was kinda poorly balanced in the mid-game. In end-game no problem.
Vampire Masquerade: I don't remember. I tried to replay it not too long ago and stopped replay when meeting some ugly boss in Nosferatu quest line. Remembered how I hated it the first time.
So yeah, the bosses I usually just forget about. They're either annoying to fight or pretty much unmemorable. In turn, I remember swathes of gameplay mid-way through, because it was simply more engaging than the generally lackluster endings.
I can relate with all that. I too enjoy the journeys far more than the destinations. Not just in games, movies as well, my favorite parts are always the beginning and the middle, the conclusions / showdowns I find far less interesting and boring. Maybe because in both games and movies I use them as a form of escapism, and what truly fascinates me is the worlds, the universes, the settings, the journeys.