Reroute that wasted energy to people you actually care about.
If you only have so much of yourself to give, why give any of it against your will? The privilege of your company is exactly that — a privilege — not a right entitled to anyone who tangentially enters the orbit of your life.
But at certain points in your life, maybe even now, you've had friends you wish you didn't have, acquaintances or friends-of-a-friend that cause a bubbling of anxiety when their presence is in your future.
Why do you hang out with them then?
Rejecting another person is one of the hardest things for a human being to do. It's why doomed relationships drag on forever and it's why ghosting happens. As a species, we don't like hurting each other's feelings, even if that person deserves it or it's what really needs to be done.
You're afraid of how you'll be perceived by "saying no" to someone else — and this extends to friendships and all relationships to a certain extent. But saying no is OK. Actually, it's more than OK; it's completely necessary for your happiness, energy and sanity.
It's difficult to pull off, but we understand it when it comes to romantic relationships. When you dread spending time with your partner, it's time to walk away. I say we need to accept that same truth when it comes to friendships.
Think of the negative outcomes of carrying out a friendship with a person you don't really like. First, you waste your time (and theirs) and time is the most valuable commodity you have to give. Your time is a zero-sum game. Every minute you spend with that unlikable "friend" is a minute that could've been spent on your yourself, or literally anything else.
Second, you're being dishonest and fake. Pretending to be somebody's friend is ultimately more hurtful than rejecting them in the first place. You're not only saying, "I don't like you," but also, "I don't care enough to tell you the truth" on top of it.
When it comes down to it, maintaining a fake friendship is akin to lying. Can you live with that?
Being friends with people you don't like is purposely polluting your own life. You're sacrificing time and causing yourself aggravation all for ... what, exactly? It's a lose-lose situation for everyone involved.