Does it make a difference if I say, ‘you are bored’ or ‘you are boring’?
(Michele, Italy)

Hi Michele, thanks for your question.
Yes, there is a difference and confusing the two could be a little embarrassing.
While both sentences describe the person, the second statement describes how the person makes others feel.  That is, if you said to someone ‘you are boring’ you are saying that they make you feel bored.
Look at this other example:
The film was boring. = The film made me feel bored.
We use the –ing adjective to describe the film. 

“It was really boring.” 

But if I want to talk about my feelings about the film – how the film made me feel, we use an –ed adjective.

“I was bored.”

There are a number of adjectives that also work this way.  Here are some of the common ones.

My weekend was exciting.  I was excited.= My weekend made me feel excited.
English can be confusing. They are confused. = The students are confused by English.
I find photography interesting.  I am interested in photography. = Photography interests me.
We had a relaxing holiday.  We felt relaxed after our holiday. = The holiday made us feel relaxed.
The example that you asked about referred to a person, using both the -ed and –ing forms.  Examples using this structure include:
My little brother is annoying.  (He makes me feel annoyed)
My little brother is annoyed. (Something is making him feel annoyed)
She felt tired after working all weekend. (Working all weekend made her feel tired)
She is tiring to work with. (She makes other people feel tired)
So, the key tip to remember is that adjectives that end with -ed talk about one's own feelings, whereas adjectives that end with -ing talk about a person, a thing or a situation that causes one's feelings.
Try these exercises
1. The election results were ........................... (disappointing/disappointed)
2. We were ........................... (surprising/surprised) to hear about their engagement.
3. The underground can be very .................................  (confusing/confused) the first time you use it.
4. I think cold, grey days in winter are very .............................(depressing/depressed)
5. She is .............. (boring/bored) with doing the same thing everyday in her job.