I frequently hear “come” when the speaker means “go” instead.

Problem:
The verbs “come” and “go” are not interchangeable.

Explanation:
Use “go” when you (or another speaker) are telling the listener to travel to a location other than where you (or another speaker) currently reside.

“Go” Examples:
1. Please go to my friend in London.
2. Jim, who today is in Houston on business, asked Mary to go to his friend in London.

Use “come” when you (or another speaker) are telling the listener to travel to a location where you (or another speaker) currently reside.

“Come” Examples:
1. Please come to me.
2. Jim, who lives in Denver, asked Mary to come to him at his temporary office in Houston.

Solution:
Use “come” when the person making the request is at the destination.
Use “go” when the person making the request is NOT at the destination.