It bothers me and makes me mad that I don't have a boyfriend?

Okay. So, what are you doing about it? Relationships don't just fall from trees.

You poor thing.
People are not possessions to grab.

You won't get one if you're always looking like you're mad about something. Try for a friendly smile.

I don't look mad bt I still don't get one

Nothing because I don't know what to talk about with guys.

That's why you need to start talking to people. Not just guys you want to date - everyone. Say hi to your neighbors, make small talk with the cashier at the checkout line at the grocery, and say something like "Nice weather we're having" to people standing in line with you or the person who gives you change at the movie theater.

That is, start learning how to break the ice in your life. Be the person who starts the conversation, because a lot of people don't, and you miss out on opportunities. Why am I suggesting talking to everyone, even someone like the middle-aged female checkout clerk at the market? Because the more conversations you have and the more you start them when the stakes are low, the easier it will be to start conversations when the stakes are high.

As for what to talk to guys about, talk to them like people - like you would talk to any of these other people I've mentioned. And if you are still really stuck about what to talk about beyond the weather, then start doing interesting things in your life. Take a class. Volunteer. Take up a hobby. Start working out. Have something to talk about.

What do I do about it if it bothers me?

When should I smile?