What I mean by this is that you establish yourself in the community as someone with lots of useful advice in a particular subject, to the point where people come and ask you questions about things similar to the subject, but not quite.
Problem is, while I know almost all things PC sound cards, I get asked for headphone and amp recommendations. A lot. And they're almost always things I have never personally tried and thus do not feel qualified to recommend or not. The least I can do is tell everyone what's in popular use, but they may still mistake it for a personal endorsement. If that's not enough, I'll tell them to let their own ears decide what's better instead of having me tell them. No advice toward a particular product is better than bad advice in my book.
I'd be more comfortable with it if I had experience with all the headphones and amps in the world, but I don't. The only headphone I really feel safe recommending at this point is a vintage set that's long discontinued and still sells for around $300-450 with a transformer box, meaning you still need a speaker amp to even use it. (I got lucky and only paid $250.) On top of that, everyone ignores its modern descendants because they're not the flagship models selling for $2,500 or even over $5,000 sans amp. The other headphones I once felt comfortable with recommending (AD700) fell out of favor due to outspoken opinions on its lack of bass driving its value down and supposedly better, cheaper alternatives (primarily SR850/HD668B) I haven't bothered to audition yet.
On top of that, I don't get sent products to review free of charge. Anything audio-related that I have opinions about is about something I paid my own money for, and I often have a hard time to try and resell the stuff without cutting my own throat on the price. (Case in point: that Recon3D USB nobody wants after I sent it to Mad Lust Envy for a review. $70 down the drain.) It's financial suicide, even moreso than just being here on Head-Fi.
The worst questions for me to deal with, though, all involve headphone amps. People keep asking me if this sound card or amp will drive their headphones or not, and when I don't even have the faintest idea what an underpowered dynamic headphone sounds like (it apparently isn't about volume), I just don't feel qualified to speak about it. On top of this, I've already taken a headphone path that requires more specialized amplification, which gives me even less incentive to put money into more conventional headphone amps.
All in all, I just feel so damn frustrated about something that really shouldn't be frustrating to begin with...