sometimes i'd say Fi in myself, because it is draining to constantly have to assess the value in everything....and it makes me feel kind of like an alien around people who aren't bothered with that sort of thing. not that i mind if they think i'm weird, but it makes it hard to be a true go with the flow hedonist most of the time with Fi as a dominant 'lens' for life... i wish i could party like some of my friends can. shit, even my 60 year old ESFP dad is better at it than i am. Fi is as great as it is daunting.
but in general, Si is my personal stumbling block. it makes me wary to trust anything new at times (despite the delightful Ne telling me to "try it and see what happens!")...i do love that it enables me to do familiar things like ride a bike or take notes with an almost unconscious fluidity and ease, but i detest how it makes me a wuss of sorts in the physical realm. it reminds me of how hard it is to learn a new mechanical skill when my Se is so weak and i have no real bearing to rely on at all... it's what helps me know my way around a familiar setting in the dark, but it's also what makes me hesitant to walk around a new space alone. Si in others can also be grating due to the expectations of what a typical anything should resemble; what qualities ought to be present and in what ratios...Si is all about "shoulds", really. and that can be truly comfortable only in what is familiar, tested, and, well...kind of boring, therefore. it makes me Ne pretty aggravated.
in others, i would say the most annoying function for me to encounter is Fe. i love sincere interactions, but Fe seems often very forced and, well, too "safe" for my tastes. like a store bought greeting card rather than a personal note with real feeling... prettier on the outside, perhaps, but lacking real substance within...yeah; nothing's worse than overly gushy, half-sincere compliments. i would really honestly rather just have someone ignore me or even directly criticize me than throw me a bunch of fake niceties because they think it's expected... there's that pesky Fi again; needs to loosen up! (but that is saying a lot that i'd prefer the criticism as an Fi-dom and all, methinks. )
cool thread idea; i seldom pass up an opportunity to complain!
edit: i didn't take into account how different functions can appear when in certain orders and in tandem with other functions...that's a whole new ramble....