Once you get into the mindset that you are going to be watching a very cheesy 70's musical there is no way you cannot enjoy this film. The dialogue is nothing amazing and it is very cheesy, but it works because the film embraces what it is rather than trying to have completely serious interactions. The comedy all works and although some of it is very exaggerated and rather silly it still feels very natural as this group of friends have so much chemistry and fun together. The quick one liners are where a lot of the comedy comes from, some of which are so quick that you might miss and pick up on the next viewing. It all comes down to the very well written characters, all of whom have very distinct and different personalities that clash and make for many very entertaining scenes. And despite there being a lot of characters, you never feel as though any of them are being completely ignored as each one is given a presence in the film, some larger than others but you feel like you know all of them.
If you have seen a few musicals, the plot of this film is absolutely nothing you haven't seen before, and it definitely plays out how you would expect it to, but it is not at all a bad thing. When you are having fun, laughing at the jokes, and singing along with the songs, the plot becomes an afterthought and you don't think about it too much, you just enjoy the film. The pacing of the film is something that personally doesn't bother me but for newcomers to the film it is probably going to be the deciding factor in whether they enjoy it or not. Some sections of the film it do slow down and they delve a little more into the romantic elements of the film which are crucial to seeing the journey these characters take throughout the film. But if you aren't as invested in these characters you won't respond to these sequences very well.
So in the end, Grease is a high school rom/com classic in the musical genre and is something that generations today can still watch and enjoy, one of the best of all time. Personally this one of my most watched films of all time believe it or not. You have your romance, your comedy, and most importantly those songs that will never leave your head whether you want them to or not. It's such a very energetic film with a talented cast and there is just an all round very good time to be had with this film.