Scenario: Guest list is too long. Groom has to cut guest list. Still too long. Groom has to cut guest list again. Many people he would like to invite cannot be invited, which he feels bad about, but it can't be helped. This is a man that does not want to see the people from work show up without an invitation. Be very sure that whether it was the bride's family, the bride, or the groom, whoever decided that the guest list couldn't include you REALLY does not want you crashing.
So your friends show up at the wedding. Now the groom has been put on the spot. They're cared enough to come to the wedding, how can he not ask them to the reception. Only his new wife had told them they were strictly limited in how many people they could have. They put in the head count a week ago. So he has to apologize that they aren't invited to the reception. Alternatively, he foolishly say, "Ah, c'mon over, we'll find you some food" earning the ire of his bride and his new in-laws. That is not the scenario a man wants to have to cope with on his wedding day.
If you're not invited and the wedding is not being held at a liturgy open to the public, don't crash the wedding or the reception. Live with the fact that few couples have the resources to invite everyone they would like to invite, and send a card of congratulations, instead.
You and your co-workers would do better to take the new couple out to dinner some time, if you want to celebrate their marriage with them. But DO NOT crash their wedding!
If the groom asks why you weren't there, you can answer, but otherwise don't bring it up. If he apologizes all over the place that you were all supposed to have been invited and weren't, you will still be outstanding among your peers as a person who was brought up correctly.
The great irony of all this, of course, is that the groom probably didn't invite the guy he respects the most, the guy who actually cares about other people's plans--that is, you--but couldn't invite everyone and didn't want the other guys at work to feel dissed. So he left all of you off of the list, only to find that the people from work how don't have social skills showed up, anyway!