Having been on for quite some time myself, I used to feel that way about getting overbid the last minute but I've found a way to get items I want without overpaying AND not get upset when I lose an auction the last few seconds..........!!
My solution......when you see an item you want, bid what you feel you'd pay for the item at a show or from another collector or better yet, the top price you'd pay for the item if you saw it ANYWHERE!!! The 'bargains' on for the really good stuff are gone.....too many people know about and participate regardless of what others may tell you about activity and it's influence on values......that's another topic !
By bidding this way, you may get an occasional bargain and never "overpay" for an item you want!
Sounds simple and for the most part it is. There's nothing worse than catching "auction fever" as you'll always overpay with that disease.

Steve