Sequels are almost always better in my experience

Nope.

Did you heard about resident evil?

Day of the dead,Aliens and Evil dead 2 are all better films.Friday the 13th also although 2 was a better movie than 4 in my opinion.Terminator is a matter of choice.Personally i liked the original better.
None of the Halloween sequels are better than the original.You said you thought part 5 was better than the original in another post.Part 5 is at the bottom of my list just above Zombies remakes and Resurrection.
No opinion on Superhero films.

I remember a character in one of the Scream movies putting up this argument to his classroom. His examples of better sequels were: Terminator 2, Aliens, Godfather, Star War Empire Strike Back. All classics, i'm sure we can agree, but exceptions to the rule. The general consensus, i'm afraid, is that sequels are generally poorer especially in the horror genre.

A few examples of my own: The Fly 2, Blair Witch 2, Blade 2, The Thing 2, Predator 2, Jaws 2, The Ring 2...

The only sequel I liked was The Godfather II

I like a lot of sequels, but I wouldn't say they're better as a rule. My favorite sequels that I like better than the original are Batman Returns, The Dark Knight, Godfather II, Friday the 13th IV The Final Chapter, T2, Bride of Chucky, and Empire Strikes Back. However there are a lot of my favorites that are the original film in a series: Halloween, Ghostbusters, El Mariachi, Sin City, Scream, Predator, Conan the Barbarian, A Nightmare on Elm Street, Jurassic Park, Scanners, Donnie Darko, Spider-Man, Dumb and Dumber, Vacation, and The Last Picture Show. Sort of a toss-up for me because a lot of those I like several sequels a lot and they contend with the original. I just like series with a crapload of entries and not having to pick which is my favorite.

Once in awhile I'll feel this way about a sequel. (Batman Returns, Addams Family Values, 22 Jump Street, The Devils Rejects) I'm not a fan of the movies you mentioned so I can't say they were better than the originals since I didn't care for the originals to begin with.

I think that if you are talking about bigger budget films then maybe some of them are. But look at the number of Direct to Video sequels that just suck. With horror movie franchises you may get one or two sequels that are just as good or surpass the original, but a lot of them end up recycled junk. When there is source material out there, ie comic books, that can continue stories in an interesting manner, sequels can work. When it's just to make more money with a lack of original ideas then we keep ending up with more Pirates of the Caribbean movies.