Have you ever had to make one? The kind that means you have to choose who your closest friends are and who are just acquaintances? This is a part of life we have to experience and it teaches us that we cannot please everyone. My mother always said, "you won't be friends with everyone you meet."
Here's a friendly "how to" with certain situations:
Party invites: don't make it headline news if they're not invited, but if they find out, a brief explanation might be needed. However, being an adult is not only your job, they have to accept that they won't always be the center of attention.
Wedding invites: this is simple; it's your wedding, you do what you want and/or have to. Weddings are expensive and our economy is sad, they'll have to understand.
Uninvited guests showing up: if it's not a bother on seating and food, or prepaid services, welcome them, maybe you'll make a new friend. If it is, you may have to tell them in a polite manner that you didn't anticipate them coming so they'll have to be patient while accommodations are made. However, if it is someone unwanted who might crash the event or is trying to ruin your happiness, a firm request for them to leave is called for. If it's an x-boyfriend, have your spouse approach them, making it more official that it is truly over.
A friend hooks you up, with another friend: if it is going nowhere, don't stay. You should know by the second date if it's a click. Be polite, but don't lie, because soon you'll end up with someone who is right, and the "I'm not ready" will slap him in the face when he finds out. Simply say, "I'm not really feeling this, and I don't want to lead you on. I'd personally rather get together as friends with
mutual friend's name goes here." When your friend asks, be real about it. If they're offended, tell them they'll have to get over it.
Gossip: we all love to dish like pigeons, but here's how to avoid backstabbing as opposed to seeking advice on how to deal with someone or chatting: "Well, I'd rather not say anything since they're not here to defend themselves." Or, "oh, I understand what you're saying, but I've never noticed that about them.
There's always a way to be polite, and at the same time honest. Sometimes, however, honesty hurts. Do not crusade to justify your every move or very existence. Think about it, do they?