My horse seems to ignore me. Your horse is not paying any attention to you. The reason is that you are likely neither paying proper attention to your horse nor talking to him clearly enough. That's not the way to talk to horses. Horses do not communicate by speech.
Horses communicate by body language and touch.
Your yelling and screaming are no more important to him than a constantly banging door. Once the novelty has gone, the sound is ignored. Just like any self respecting two year old child. No, I don't expect anything. But, if you want to work successfully with horses, you are going to have to learn to talk and understand the language of horses.