1) My Funk - Tank green with Communist Red girvin vectors. Swapped it with my ex for a microwave when we split (microwave lasted 1 month after that).
2) Titan 1/2 Trak. Massive bike, but lovely all the same (still got the 1 1/4" fillet brazed negative rise stem for this somewhere)
3) My Bonty Race OR, sold it, bought it back, sold it, then got sold on to someone on here so I keep having to see it (bit like seeing that pretty ex down the local every week

)
4) Red precision shifters and mechs (so I could go nine speed - what was I thinking)
5) Dekerf ahead Ti bar stem combo - would have gone so well on my Seven - but at the time none of my bikes were 1 1/8" so could justify keeping it as it didn't work with shims
Nearly..
1) Almost sold my Slingshot Road bike, but bottled in the end and how glad am I.
2) Almost swapped my Fat Ti at Recycle (I used Recycle like a lending library, swapping frames, bikes and kit every few months. Swapped a Kawasaki green San Andreas frame for the Fat Ti, but was sorely tempted by a Chuck hardtail a few months later)
3) Was going to sell my Turner XCE but the GF wanted a bike so it got built up again and looks great (possibly the best 'non -biking Girlfriend bike in the world!)
After that I learnt that the key thing to do is hold on to everything for a number of years in boxes under the stairs until you've forgotten you own it. Best thing then is to give stuff away for peanuts or swap it with some one who 'really' needs it, then you have the nice fuzzy glow rather than the constant thought of 'why?'.