At my old job when they'd pass the birthday card around I'd hold onto it longer than most--fretting over what I was going to say and reading what other people had written. They always wrote wonderfully personal sentiments that I could never match. My friend Brian would usually write something border-line offensive/incredibly funny. You could tell he just wrote it off the cuff and without thinking, yet it was always so apropos and clever. People would later remark about how funny Brian's comment was.
Eventually the company got bigger and the birthday card passing was phased out. If you wanted to you could go downstairs and sign the card they'd leave on the table, but I was thankful I didn't have to participate anymore. I always wanted to say just the right thing, and I'd spend so much damn time trying to come up with something, eventually (sometimes after a whole day) I'd wuss out and write "Happy Birthday! Andre".
Even then I'd torture myself over whether I should put the exclamation mark in and whether a comma would sound too insincere. "But is the exclamation point too festive?" I would fret. Then, after I wrote it and handed it to the next person, I'd wonder if everyone was thinking I was mildly retarded since I basically just yelled happy birthday on a card that said "Happy Birthday" on the front.
So at FM everyone is incredibly supportive and friendly. When the sales group lands a big sale there is a nice flurry of CC'd email congratulating them and jokes about the beer being on their tab tonight. I usually find myself panicked that I don't have anything to say. "Hooray!" sounds silly. "Way To Go!" just isn't me. I want to join in but when I realized I have just spent 10 minutes trying to come up with something more than "Woot", I give up and go back to work.
Today I tried to congratulate someone with an "off the cuff sounding but really not that off the cuff because I spent 5 minutes on it": "WTG, _____!" (Way To Go) message of support for their hard work on some data for a presentation. The reply was, basically: "I didn't do that, your boss who you CC'd did."