As a country we have a reputation for being almost professionally nonchalant when it comes to celebrities and it's mostly deserved. Last week I watched acting legend Brendan Gleeson sit down for a drink after the opening night of Enda Walsh's The Walworth Farce in the Olympia theatre and have a chat with his mates without being remotely hassled by fawning fans and hangers-on telling him how utterly magnificent he and his sons were in the play.

“If this was New York, that would never happen, he’d be mobbed by now,” said one of my group sitting professionally nonchalant at the next table as we rushed to fill the admiring silence we had accidentally allowed to replace our conversation as the actor arrived.

I say that reputation for nonchalance in the face of celebrity is “mostly deserved” because it’s a reputation that is ruined completely by me and by dopes like me who cannot see a well known person, especially one we like, and not acknowledge them verbally in some way. It’s a pathetic affliction I suffered badly with before getting into journalism and which only got worse when I found myself in a position where I occasionally came across well known people through work.

I just can't help myself. Singing A Good Heart (Is Hard To Find) at Feargal Sharkey. Loudly humming the Riverdance tune at Jean Butler. Telling Dermot Morgan my sister served him once in the local video shop. Going up to Stephen Fry years ago and quoting random lines from Fry and Laurie sketches to him as he tried to talk to his friend. Trying to engage Leo Varadkar in a chat about lunch options as he queued up in front of me at the sushi joint near both our offices. Following your woman Stefanie Powers into a toilet in Palm Springs to tell her how much I loved Hart to Hart. Once (also in a bathroom), I told a very pretty woman who looked very like Winona Ryder how much she looked like her and how much I loved the actor's work. It was only afterwards that someone told me the very pretty woman actually was Winona Ryder. In the annals of random celebrity encounters, she is the one that got away.

I am also one of those people who regularly insists to well known people or actors that I've met them somewhere before. When I was introduced to a man recently, I told him we'd definitely already met and he insisted that no we definitely hadn't. Of course I couldn't let it go. I brought it up a couple of more times, trying to figure out the conundrum, until a kind person took me aside and told me I only thought I knew him because he had played the dentist in Love/Hate.

When I interview well known people for my podcast, I can usually keep it together for professional reasons, but when I come across them unexpectedly, going about my daily business, I tend to get highly distracted by the familiarity of their faces and forget how to speak. "You play X in X don't you?" is all I can usually manage before standing and grinning at them. I've been collecting encounters with people from Fair City for years. They include Detective Deegan, Orla who owns McCoys, and the fireman character who used to be in it. Last year, someone I actually know in real life joined the cast of Fair City and I don't know how I'm going to cope when I bump into him again.

I’ve seen the other side of these encounters, sometimes getting approached by readers of this column. Once I was stopped by a reader when I was shopping for underwear which even I wouldn’t have the nerve to do, so bravo to that woman. Mostly, it’s people apologising for bothering me and feeling bad for interrupting whatever I’m doing. But as a compulsive compliment-giver from the A to the Z list of celebrity, I always appreciate them going to the bother and admire how they form intelligible sentences.

That night of The Walworth Farce, which by the way, you need to go and see even if you are not a theatre person, and maybe especially if you are not a theatre person, was a mixed success. On the up side, I managed to speak vaguely sensibly to Domhnall Gleeson about the affect his movie About Time had on me. Then his da Brendan Gleeson passed by me on his way out. "You did brilliant in the play, real good it was," I said, not quite to him, but to the air beside his head. At this stage of my life I have accepted that I will never be good at these encounters but that they will always, always give me a ridiculous kind of thrill.

roisin@irishtimes.com