What was the problem between Snape and James Potter?

In my opinion, there wasn't a good reason. It started when they were in the train and the way Snape acted... I suppose it represented everything that James disliked about Slytherin. All Snape dicho was "you better be in Slytherin" to Lilly and James heard that and put down the house. Snape retaliated por dissing Gryffindor and then James called him "Snivellus" and Lilly and Snape left the train compartment. Seriously, that seemed to be the first incident. Very lame.

But ever since then they hated each other and whenever James and the Marauders bullied him (for the reason of "because he exists") Snape fought back and was never nice to them. So it just continued.

Later on, it was probably 'cause James like Lilly and Snape liked Lilly and Snape and Lilly were friends and Lilly was always defending the opposite person with one of them... Jealousy. Then Snape got into the Dark Arts and James hated the Dark Arts and Snape seemed más like a Slytherin stereotype.

And what is the difference between a child who has everithing and one who has nothing! The problem existed from the very beginning: James was loved por his parents he had a lot of friends;Snape's parents didn't care about him, his only amor was Lily-but she left him for James! How to live with a broken corazón and not to hate the one who estola the amor of your life?!

They both liked Lily, and James wound up being the one going out with her. Also, James was mean to Snape and was always pulling pranks on him.

er...snape was a dickhead to harry?

they both loved lily but james got her in the end so snape got jealous and took it out on harry

Snape & James amor Lily and Lily with James so Snape hate James!!!! it's all! XD

Severus was always in amor with Lily Potter since they were kids but Lily never saw Severus in that way he was just a friend and then, when they go to Hogwarts James and Lily fell in amor (not this fast, of course)... Severus doesn´t like James cause he took Lily from him

from the beggining snape and lilly were friends
james, suris, lupin and wormtail made fun of him (well lupin did not) since when they first meet because he wanted lilly to be in slytharin they heard what he dicho and also because they wanted fun then lilly stoped being his friend and started to fecha james simple

(its all of the above)

It just happend when James dicho He wanted to be in Griffindor and Snape snorted.and dicho he wanted to be in Slytherin.And well they never really liked each other and Lily was alway hanging out with Snape not James.And Griffindors and Slytherins never liked each other!!

the same problem with harry and draco

James knew snape loved lily, so he obviously despised him
but he did save his life at one point
that's why in the first movie snape saves harry from quirrel's curse on his broom
to make them even :)