Good topic but why is it in the " beginner discussion" forum?
I once toured a fellow New Englanders massive home built orchid greenhouse that was roughly 40 ft x 100 ft and held a collection of at least 2000 mature orchids. When I got to the area that housed an office, mechanical systems, potting area and supplies I noticed 3 large (I think they were maybe 3# each) coffee cans stuffed full of plant tags.
When I asked him about them he shrugged his shoulders, laughed and said "If you're not killing a few, you're not learning anything". How true!
I haven't racked up that many yet but I've done in my fair share and then some probably.
Thinking about it, I think there have been 3 that were particularly painful.
1) a specimen awarded Sedeira japonica I bought at an auction.
2) a Catt. dowiana
3) Dendrophylax lindenii (enough said!)
If at first you don't succeed, try, try again!