I don't think it's a 'secret admirer' or it was meant to be romantic or creepy. Honestly, I figure it was someone just trying to be nice and didn't realize the lack of note might make it seem otherwise. I mean creepy would be a videotape of me going about my day or photos of where I live, undergarments, or used Kleenex. Now that would be beyond creepy and cause concern. This was just peanut butter.
or taking photos of you in the airport. Maybe it was him.
Shaney stole my idea - check the travel threads and build up a list of suspects. Then interrogate them one by one by tying them to a chair, shining a bright light in their face and periodically beating them. One of them will admit to it eventually.
Otherwise you could contact US or Irish Immigration for a full list of people who have travelled between our 2 countries in the last 6 months. Unless of course they connected through another country, in which case you'll have to contact Immigration in every country in the world.
I can honestly say you've never mentioned that brand of peanut butter to me, so unless you can find where you've mentioned it on here, start wracking your brains to think who you might have actually mentioned it to.
Maybe somebody gave it to somebody to drop into your workpace, to throw you off the scent.
Also, back to CCTV. Talk to security in there. Tell them you're creeped out. They'll sympathise I'm sure. If not, start crying when you're talking to them. They won't know what to do and will cooperate to get you to stop.
It might have been Spencer. You never know. Actually, not knowing is probably better cos you can try and convince yourself it was him.
Edit: This thread is the type of thing that award-winning websites are made of imo