I'm tired of this boring lesson!

Participles such as interesting, frightening, bored, boring, etc.  can be used as adjectives.

 Read the following examples:

-ED participles say how people feel	-ING participles describe the people or things that cause the feelings
I was very tired after the long journey.	It was a very tiring journey.
The children were really excited.	What an exciting adventure it was!
If you are so bored, why don’t you go to bed?	It’s the most boring film I have ever watched.
I’m not interested in water sports.	Doing voluntary work is an interesting experience.
She sounded a bit confused.	It’s a very confusing text.
Everybody was terrified.	It was a terrifying story.
I felt relaxed and confident.	I had a relaxing bath.

Be very careful in cases where you use only one adjective in Spanish: “cansado” and “aburrido” can mean two very different things, depending on whether you mean ESTAR o SER.

Don’t say “-ED for people, -ING for things” because people can be both boring and bored, tiring and tired.

If you are not sure whether to use -ED or –ING, remember the following rule:

Usamos –ED para ESTAR: alguien ESTÁ cansado / emocionado / aburrido / interesado / confundido / aterrado / relajado.

Usamos –ING para SER: algo o alguien ES cansado (=agotador) / emocionante / aburrido (=pesado)/ interesante / confuso / terrorífico.