Let's talk about eye contact!
This is something that we as humans naturally do - staring at someone is a sign of interest and often respect and attentiveness. So, when we meet a new dog friend, we often default to this method of human non-verbal communication.
This is not great communication in dog language, though. Staring is not "polite" dog communication in most cases - when you see two dogs staring at each other, this is not a calm, polite interaction. When communicating with each other, dogs choose more side-by-side communication methods.
When you are approaching a dog you don't know, it's best to adopt this preferred dog communication strategy. Instead of staring, think about turning your body and eyes to the side as the dog approaches. Allow the dog to direct the level of interaction they are comfortable with. Avoid hard staring until the dog has made friends with you.