If you answered yes to the second picture, does it bother you? If not, carry on and stitch away! I envy you. If you answered yes to the second picture and it bothers you, well now is the time to get organized before you end up with ten tubs looking like that and give up stitching forever!
First, allocate a couple of hours for the first step. If you're in a hurry, it will never work. Find a large clean area where the kids and the dogs and cats won't bother you. I know...there is no such place. Do your best. Try the bed in the guest room, assuming no one is coming to visit until Easter. Dump the mess of floss on the bed and pull out all the 'clean' skeins. By 'clean', I mean, still usable with the identifying brand and number and/or color name attached. Doing this first will give you a sense of accomplishment and will stave off waves of despair that might drown you if you started with the tangled messy ones. Sort them by brand and then by number/name. Now treat yourself to a couple of Oreos and a glass of milk. If one of your resolutions was some form of healthy nutrition, treat yourself to 15 minutes of stitching.
Second, tackle the messy ones that still have labels with identifiers on them. If the tangles are easily untangled, do so, if you are feeling frugal. But don't do more than ten at a time. It's too depressing. If you don't care about wasting thread or the tangles are worse than a teased mess of a 1950's hair-do, cut out the tangled, knotted pieces and save what you can.
Now this may takes days or even weeks depending on how long you've been stuffing leftover floss in the tub. Just allocate an hour a day to it. At some point you will want to decide how to store your neatly organized threads. Some people used little cards like the top picture. Others like zip-lock bags. Whatever you choose, have lots of them available! You don't want to lose momentum in the middle of the task. And don't forget to label them. As you go along, keep an inventory list of the various brands of floss and the numbers/names. When you find a color in the mess that you're sure you've seen before, you can check the list and add the new one to the existing one. (Make note of dye lot differences.)
If you win the lottery while suffering through this self imposed torture, toss the whole mess in the garbage and buy all new! Just try to stay organized when you start fresh!