I thought of another one, and FWIW, I could probably keep this thread going for some time to come!
Fishing out of Katmai Lodge I had the good fortune of taking on three English gentlemen, one was a Gilly by trade, another a heir to wealth, and the third a resort hotel tycoon. That has really little to do with the story but it frames the three of them up.
Somewhere in the middle of their trip I had a fly out to Brooks Lodge. For those that don't know Brooks is a federally protected area that contains a section of Brooks Lake, all of Brooks River and a section of Lake Naknek. It is world renowned for it's large population of Alaska Brown bear and the bear viewing area at Brooks Falls.

The trip to Brooks was uneventful, but I knew going in that the natives had been netting Naknek River for the last week, harvesting a large portion of the Sockeye population so fishing for sockeye was going to be difficult at best. We'd likely have to focus our attention on Brooks River to be successful on this trip and target the grayling and rainbows, keeping in mind that fishing Brooks River is like running the gauntlet with 29 resident Brown Bear known to inhabit the area territorially not to mention the transients.
Once at Brooks and a brief walk down to the lake it was apparent that there were very few sockeye, in fact the bears outnumbered the fish. Two of my party had decided in proper English tradition that the morning would be best spent working on a bottle of single malt while the Gilly (guide by our terms) decided he'd try his hand at the Sockeye. I took the lone fisherman to the headwaters of the river at Brooks and he started fishing.
All around us were Brown Bears, yawning (a sign of stress - go figure - no fish) and pacing back and forth. Much to my surprise my guy hooks a fish and the fly reel started singing as the fish ran. He actually caught a fish! In these conditions what are the odds?!? Anyway that reel sounded like a dinner bell at a thanksgiving fiest because a half dozen bear turned their attention to the sound. I surveyed the situation and after about 20 seconds told him to break the line off. He replied, "I paid five thousand dollars to take this trip and I'll be damned if I'm breaking this fish off", at which time I took the rod from him, pointed it at the fish, clamped down on the line and snapped the fish off. But it was a case of too little too late.
Across the river we had a bear trying to decide whether to swim over to us or stay put, and to our right we had a bear closing in at a trot about 100 yards out. To our left there was a curious bear just looking and about another 100 yards beyond was another bear closing on our position quickly. Still to our left the bear that was further out was coming over a birm and surprised the bear to our left that was as I said curious. A fight immediately ensued between the two. We were backing away from the river steadily with no where to go. The bear to our right was now in front of us, between us and the bridge across the river to the lodge. We had no escape. The bears to our left were still fighting. The bear in front of us approached to within 6 feet of me. I'd tell you that the bear easily weighed 1500 lbs but in reality it was probably closer to 1000 to 1200. Still he was absolutely immense! The bear roared a few times and all the while stayed on four legs, he reared back on his back legs and pounced the ground, snorted, spit, shook his head from side to side and roared again, and snorted and spit. He kept on pounding the ground with his front paws. He weighed so much and was hitting the ground with such furosity that the ground was noticably shaking. The hackles on his shoulders stook straight off his body making him look twice as big as he already looked, like that really mattered at this point. With one last terrifying act he lunged forward about a foot and lowered his head as he roared one final time before turning around and laying down on the bridge, as if to say you really pissed me off, now just try and get back across here.
An hour or so later he got up and moved and everything else went back to normal, as normal could get after that experience. Somewhere in the middle of all the comotion the other two bears quite fighting, and the bear accross the river had decided to go someplace else.
Once across the river my guy headed straight for the lodge and decided he was going to put a serious dent in the bar stock.
I determined at that point that while Brooks was a very beautiful area, I really didn't need to go back again, nor will I ever! Later that year a bear mauled and mamed a ranger (survived the attack), the first ever...