First dates can be a lot like dentist appointments: They seem like a good idea when you are making them, but when the time actually comes, you find yourself thinking of a dozen and one ways to get out of them.

This is mostly because first dates can just be so incredibly awkward.

Chances are you barely know the person you are having a first date with, and that means you are both trying to impress each other. But there is a fine line between being on your best behavior and trying to pretend that you're someone you are not.

Many times, the harder you work at dazzling your date, the greater the likelihood that you will completely blow your chances of ever seeing them again.

Here's a look at five first date mistakes you should avoid at all costs ...

cocky man smoking cigar on date with woman

No. 5: Trying too hard

Trying too hard is one of the worst things you can do on a first date.

It either makes you come across as insecure and awkward, or cocky and obnoxious. And none of these are qualities that are going to have people lining up around the block to go out with you.

It may sound clichéd, but just being yourself is the best way to impress. That is, of course, your "better" self. Leave the side of you that picks your nose and sings off-key to Justin Timberlake songs at home.

At the same time, try not to brag, exaggerate, lie or pretend to be someone you're not. Telling your date you're a marine biologist when you're unemployed and living with your parents will only end up in disaster.

Just ask George Costanza. And while you're at it, ask yourself this next question ...

couple arguing on a bad date

No. 4: Assuming too much

Every first date has a point, a goal.

Either you are looking for just a casual good time, or you are hoping the first date will evolve into a second and a third and maybe even a lifetime. One of the quickest ways to blow a first date is to assume that your date is on the same page that you are.

Making sexual overtures to someone who is hoping for a long-term courtship is likely to go over about as well as a 300-pound pole vaulter. In fact, as a general rule, sex should not be a first-date topic, even if it is your ultimate goal.

Talking about sex with a virtual stranger tends to reek of desperation. Of course, that's better than reeking of B.O., but neither are likely to win you any points.

And neither is our next big mistake ...

couple on awkward first date