When cycling you should always ride the direction of traffic for yours and others safety. There are many reasons why you have to do this.
Reasons why cyclists ride in the same direction of traffic
Most states have laws stating that cyclists need to ride with the direction of traffic. If there is some sort of accident and you are riding on the wrong side of the road it will be legally your fault.
Pedestrians walk against traffic; this gives them lots of time to see cyclists coming. If pedestrians don’t see you coming, they could easily accidently step in your way causing you to collide or turn into a car trying to avoid the pedestrian.
Now if cyclists are passing each other in different directions this could again cause a collision or lead to one cyclist turning into traffic to avoid a collision.
If you are going the same direction as traffic there will be fewer passing vehicles, and they will be going slower relative to your speed. If going against traffic their speed will be amplified by yours, and you will have more pass due to driving into them rather than away. The force of impact if hit by a car going the opposite direction is also much greater as your speed it added to theirs rather than subtracted if going in the same direction.
While driving, I recently had to pass a cyclist going on the wrong side of the road at night on a dark road. I just suddenly saw a headlight in front of me on my side of the road. I didn’t know if it was a bike, motorcycle, or car with a headlight out. It made me very uncomfortable not knowing if there would be a collision.
Cars making a right turn will not expect a quickly approaching cyclist on their side of the road. They are looking to their left to make sure the turn is clear. They could easily turn right into a cyclist.
Cars leaving their driveway won’t be looking for cyclists on the wrong side of the road. They likely won’t see you and will back out right in front of you.