I'm always a little wary of people who say they're "very" anything. Partly because it's boasting, and that's Not Done, but mostly, it's because I usually don't believe them.
This may only be a foolhardy prejudice. You see, the people I know who are "very" tend not to mention it. They say something like "I've been trying to master how to play the cello with my teeth, now that I've learnt to play it with all of my limbs, but I just can't seem to grip the bow tight enough. It's very disappointing." or, when you're blindsided by their talents in the form of a tennis ball that makes that sonic boom noise, "Well, I have been taking lessons for six months now. It's a great help."
By which, I obviously mean to say that all the "very" people I know are crazy.
It's not that they don't know they're good at something - they just know that a) other people have also done this and b) they could be better. Most of the time c) other people are currently doing it better/younger/backwards also applies. When someone tells me they're "very" good at something, I always wonder how many people are doing it better or - more often - why their great intelligence, wit, and encyclopedic knowledge haven't spilled over into every day life: where, I want to know, is the show that goes with the tell?
I try not to ask these questions out loud. These are the kind of questions that people are very definitely not keen on.
Sometimes, however, it's not only an accurate self assesment, but useful. I'd love to know, to take a random example, that you think you're a very bad driver before we arrange for you to pick me up, or that you are very allergic to, well, anything really, particularly if I'm making dinner.
Being an untrusting, sceptical wretch, I'd quite often like to ask for supporting documentation, particularly if it's important, and not just in an "OK, so you say you're a very good pilot" way. The things people say about themselves are an important part of forming your opinion, and if you don't believe them, that puts something of a dent in the proto-friendship.
But on the other hand, this modesty thing can be very tiresome, and makes finding balanced groups for activities tricky, and certainly makes social story telling more awkward. Perhaps we should abandon it for a while, and not only say what we think, but also ask the clarifying questions society usually prohibits? Maybe next time someone tells me they're very smart, or very well read (because these are rather easier for me to take pot shots at than, say a claim to be a very good rally driver), I won't bite my tongue and smile, but instead ask for evidence. What, I will demand, does being well read mean to you? The classics? Of which country? In translation? Well! And so on, until I can prove to my own satisfaction that I was right not to believe them in the first place or, failing that, restort to nodding, smiling, and running away.
Of course, being very much a social coward, I will very likely be only doing this in my head.