So I really don't like it when the girl and the guy get together early and stay a couple all the way to the end that is why on my list you will see a lot of drops since I watch them till they get together. I just don't enjoy watching couples but I really like the part where I watch how they get together. So pretty much I like the chase for me that is the most exciting part of the relationship to watch.

So I want to see a drama where the main couple get together in the very end and the whole drama is about how they get there. I do prefer it having love triangles also if possible.
Dokushin Kizoku (+ triangle)
Sprout (+ triangle, teenagers though)
Soratobu Kouhoushitsu (no triangle)
Chinese drama BEST TIME http://mydramalist.com/4262-best-time does this pretty well imho. Tons of angst, and Wallace Chung is supremely talented at creating angst imho.
In the Witch's romance based on the synopsis "sparks fly" when they meet I infer they get together right away. Is that true?
in Witch's Romance, they did not get together right away. but the guy was inlove almost instantly
I was going to suggest Secret Garden but I see its on your dropped list. One of my top favorites. The guy (Hyun Bin)keeps chasing the girl (Ha Ji Won) since she is ignoring him. You know, typical rich arrogant guy and poosr girl trying to live her life.The girl isn't interested at all with the guy but has a major crush on his celebrity cousin.  Lol. But how they fall in love and got together is one of the reason why you should watch it.

Anyway, Reply 1997 is the closest I can think of. The guy isn't chasing the girl since they are best friends since grade school. How they got together, well there's a lot to tell but give it a try, its a sweet story.
We may be the opposite since I can't stand it when it takes forever for the leads to get together, but the first one I thought of was Shining Inheritance. It may not fit the bill exactly, and it's a bit longer than other dramas on your list (28 episodes), but it does take quite a while for the leads to get together (it's more of a slow build as it takes them a while to develop feelings as well). I really enjoyed the drama, despite the fact that the wait for them to get together drove me crazy, but you may like that about it, and there is a love triangle as well.
THX a lot guys going to check some of these out. As for Secret Garden honestly I loved the female character its just that I can't stand the main male lead. 
In Time With You- Although, it seems you're not into Taiwanese dramas, this is exactly what you're looking for.
I Need Romance 3
I Really Really Like You
Dr. Champ
Biscuit Teacher Star Candy

All of these dramas have the guy chasing the girl. Also, the girl likes someone else, which creates the love triangle.
I feel the same way, I usually drop a drama is relationship is developing too fast. Here is what I would recommend.

Sorry I love you -  Not the most happiest of dramas, but So ji Sub and Im Su Jeong were great in this! I'm usually not one for the melodrama but the chemistry between them was crazy. I would recommend this drama the most just because the two leads have such believable chemistry between them and it makes the whole "chase" even better. if i remember correctly Im su Jeong's character likes someone else which makes the love triangle (kind of) Beware though you will shed tears lol.