I'm along your lines. If I happened to have a stash of bitcoins in my pocket, I'd be very careful about actually buying anything with them today, as the next week they would be more and more valuable. So I think the deflation is the main reason why I don't feel comfortable with idea of using bitcoins as a currency for buying anything - selling might be a different story.
edit: How large volumes of selling bitcoins for USD/EUR/etc. is enough to have significant effect on the value of bitcoin? For example if I had VERY URGENT need to sell 100 000 bitcoins by tomorrow in exchange for USD.
edit: How large volumes of selling bitcoins for USD/EUR/etc. is enough to have significant effect on the value of bitcoin? For example if I had VERY URGENT need to sell 100 000 bitcoins by tomorrow in exchange for USD.