My hearing is usually normal but i still have trouble understanding speech in restaurant. why?

Likely distractions: Even with normal hearing, some people can find hearing in noisy places makes it tough. Distractions can be a problem for some people, and their brains may not be able to filter one thing out from the rest. And if your hearing is on the low end of normal, or if it has decreased from your normal, you may have relative hearing loss as this problem is common as hearing decreases.