AAAAA,

I would not necessarily look at this experience as simply a break in your 20 year streak w/out having lost your cool. I know it sounds cliche, but look at it as a learning experience and a chance to strengthen your ability to prevent future meltdowns.

Who knows, if it hadn't been this co-worker, it might have been something else. You sound tuned in and intelligent, so I know you know this, but you cannot control this person at work or many of the external stimuli and stressors that come your way. You can only control your reaction to them and/ or be proactive in preventing these stressors from getting the best of you.

Perhaps it won't be effective in your particular case, but you might want to consider writing a letter to anyone involved that you deem appropriate, keeping the focus on your behavior w/out even mentioning the co-worker. I lost my cool once, and a heartfelt apology for my behavior went a really long way towards repairing the damage. In fact, I developed a closer bond to my supervisor (sadly, she's gone now...the new one is not so great) than ever before. She made a point to thank me for the letter and said it meant a lot, and we still keep in touch in fact. I really felt like it cleared the air, so to speak, and I was able to express myself so much better in a letter than I ever could have face-to-face.

Those HR meetings sound so horrendous. Definitely not conducive (unfortunately) to open and honest communication. They sound about as effective as performance evaluations.

Anyway, if you went 20 years w/out any temper flare ups, you have CLEARLY demonstrated that you are in control of your emotions, so again, this can be viewed as an anomaly to otherwise consistently appropriate behavior and demeanor. There's no reason why you can't get right back on track while taking some lessons away from this experience on how to avoid a similar situation in the future.

Anyway, best of luck to you, and don't be too hard on yourself.