I'm aware the honeymoon period plays a part, but still.
Some people seem to think that in the first 3/6/9 or however many months of the relationship that everything should be perfect and amazing all of the time, that there should be no argument and that people should be on their 'best behaviour'.
Why not be your authentic self from day one ?
There's a lot of 'if he's like this after 3 months, imagine what he's like after 3 years'.
So at what point does it become a normal relationship where people let their mask slip ?