Dear {Name},
I'm sorry for bothering you the other day. I didn't realize you {were busy/don't give out free advice/etc.}. I was only thinking of myself and my own situation and should not have imposed.
I appreciate your willingness to help me out in the past and I hope to return the favor sometime. I apologize, too, for my {bad timing/bluntness/etc.}.
Sincerely,
{Name}
Download this apology letter template — free!
Formatted and ready to use with Microsoft Word, Google Docs, or any other word processor that can open the .DOC file format.
Index of letter of apology templates