What does trademark law say about using one's given, legal name that was not intentionally selected to resemble an existing trademark in trade when it does, in

What does trademark law say about using one's given, legal name that was not intentionally selected to resemble an existing trademark in trade when it does, in fact resemble such a trademark? I don't think it's as clear-cut as you suggest, though admitting to choosing the domain name because it resembles Microsoft is a bad move from a legal perspective.