Sad, yes- that's OK. Depressed, well I try to keep away from that one too, but I realise it's not so much within my power.
But bored- that's wilful. That's an attitude of mind. A pose. It can be avoided.
It's a teen thing. It goes with growing pains and thwarted impulses. I'm a grown up, well-educated human being. I have resources.
There's books and movies and newspapers and websites. There's even other human beings.
There's jobs to be done. There's daydreams.
I just repaired the (very large) cardboard box the rabbits use as a warren. They'd eaten away one whole wall, so I patched it up for them. My, that was bracing! That was invigorating!
To be bored is to insult the Creator (if there is one). I don't generally have a problem about being rude to the gods (often they deserve it) but in this case it's just so unfair. This world has loads wrong with it but you can't say it's not interesting. It's too full of stuff (much of it horrible) to be boring.
As Stevenson said,
The world is so full of of a number of things.
I'm sure we should all be as happy as kings.