4. Those who belittle you in front of your partner.
Now, this is a rather strange kind of friendship. Your friend knows that your someone special is around and instead of rooting for you in front of them, they start belittling you. They will talk about all your negative habits. They will bring up your past and ridicule you over it. In short, they will just try to present you as a horrible person in front of your partner. Such kind of sadistic people should not be called friends because they are only trying to bring you down. There is a weird class of people who feel good by bringing other people down and you must always stay away from them.
3. The date-crashers.
This kind of friends definitely ruins your relationship. It is funny every once in awhile when your friends crash your date. However, if they do it all the time, they are definitely ruining your relationship. You see, when two partners decide to go on a date, they take out time to be with each other. They want to sit and talk and relax together in whatever place they are comfortable in. They share this with their friends because they are excited about having a chance to do something like this. However, their friends should be understanding of the fact that the two people need time with each other. If they crash their dates, they are only making a little wrong for the two because they are taking away their personal time.