I have no issue with bickering friends, but the way the movie showed that was a bit too hostile. Why rag on Poe for being a spice runner when Finn was a clone trooper? It just all seemed out of leftfield. They even had a fallout midway through the movie. It just didn’t feel deserved.
Didn’t seem hostile at all to me. The reveal that Poe used to smuggle slave-mined drugs is perfectly deserving of the brief shock that Finn and Rey have, but Poe quickly dissolves the tension by pointing out exactly what you yourself just pointed out, and it really isn’t much of a problem after. Friends don’t get along all the time, especially in tense situations or when secrets are involved, and there’s still enough camaraderie and weak jabs between the two to sell their relationship as a real friendship. They do have a confrontation near the Death Star II about Poe’s leadership, but it’s resolved the next time they’re together and is an incredibly basic trope of storytelling.
In contrast, to use another Star Wars as an example, Anakin’s constant heated arguments with Obi-Wan and Padme in the prequels are incredibly uncomfortable to watch and make their “friendships/love” completely unbelievable.