I've had an interest in fonts1 since I was a teenager. I've never represented myself as an expert in typography or font design, but I can pick out a few more specific fonts than most people and I occasionally have strong opinions about which ones people should (or more often shouldn't) have used in a given piece of text.
Some of those opinions are basically orthodox: Comic Sans is the wrong font for almost anything, Arial is slightly inferior to Helvetica.
Some of them are really quite strong: when I was a teenager I used to find that text in Souvenir made me feel physically ill. I have a stronger stomach these days, admittedly, but I still think it's pretty ugly.
Also, I go off fonts due to overuse. I haven't been able to look Garamond in the face since I was about fifteen, not because there's anything wrong with it but solely because at that age I had occasional employment DTPing a lot of internal quality control forms for a friend's dad's small business; their house style involved Garamond (or some indistinguishable cheap knockoff of it) and after a while I found I was heartily sick of it because it reminded me of that work.
What's particularly annoying to me, though, is when I go off a font that I had particularly liked before. I used to be very fond of Utopia, for instance, and was therefore delighted that it was readily available in free software distributions. However, it turned out that its distinctively square look was a nice place to visit but not somewhere I'd want to live.
Another one in this category, in fact even more so, is Bembo, which seems like quite a popular font to use for (among other things) SF books. When I first noticed Bembo I really liked it, because although the base form is yet another unremarkable serif font, its italics are distinctive (by their narrow and slightly pointy general shape, and also notably the squashed g and the serif at the bottom of the y) and gorgeous. It has one practical downside that I've noticed, namely that the tail on the (roman) R is long enough to put large and unsightly spaces in the middle of all-caps text (one of the Red Dwarf novels, I recall, failed to notice this before using it); but if you avoided that trap it was lovely.
Unfortunately, everyone seems to have noticed this, and the effect is that it's become so overused that I now can't see it without feeling a bit bored by it. And that's really annoying, because it is gorgeous and I entirely understand why people still use it.
It's particularly annoying because I normally have relatively little patience with changing fashions; I don't want to be the sort of person who cares whether some given thing is this year's or last year's fashion, I want to be the sort who judges as objectively as possible whether it looks good and lets that be an end of it. I realise that my aesthetic perceptions will be subconsciously influenced by my changing environment in spite of my best efforts in this area, but at the very least I want to be the sort of person who digs in his heels and resists that fact to the limits of his ability rather than embracing it enthusiastically. So to begin disliking a font which I still think is gorgeous on the basis that it's overused represents something of a failure for me, and that annoys me even more than the overuse of the font itself.
(I'm inspired to post this by having been irritated by both Utopia and Bembo over the course of the weekend, which caused what's normally a subconscious irritation to come to the surface of my brain and allow me to see exactly what was irritating about it.)
1. yes, yes, ‘typefaces’ is more accurate, but the difference isn't critical to anything I do, and ‘font’ is faster to type and say.