I used to collect it until I'd find someone questing those items then I'd dump it all on them, but now that I"m questing I sell it in the MP each day save one day that I use to donate whatever I gather to a friend for her quest lol.
I collect trash/junk and sell them. I don't care enough about keeping them/using them, and there are people out there who do want them. Everyone wins! I keep all my bugs and turn them into ink, though.
I'm definitely a hoarder. Even in real life I can't let things go easily (but I don't keep actual trash xp). My inventory is full of trash, and I am actively collecting lake trash to trade in for items as my current quest. Most of the insects/flowers/trash just sit in my inventory, but its all neatly organized so I don't mind having them there - and I like seeing the numbers next to them go up as well.