You should support someone who is working for their dreams.
John is talking to his friend Kim who tells John that he's going to try to make it to the NBA.
John wants to respond to Kim's statement.
John tells Kim that it will be really difficult, but he believes in Kim and if he can help somehow he will.
John tells Kim that he's being ridiculous and that he would never make it so it'll just be a huge waste of time.
Kim is really happy that John believes in him and his confidence in himself is increased.
Kim is insulted that John has no belief in him and at the same time discouraged from continuing on with his dream.