Brussel Sprouts are an absolutely FABULOUS & vastly underused vegetable. Most people who dislike them do so because they remember being served old, seriously overcooked, mushy, bitter sprouts. Blech - even I wouldn't like them like that!!
Your best bet to enjoy them at their finest? Try to avoid purchasing fresh sprouts in those little plastic-covered containers. You really want to be able to pick & choose them from an open bin, or buy them fresh on the stalk - a marketing method becoming more frequent than it's usual spot at local farm stands. Choose tight little sprouts without yellowing leaves, etc. If good-quality fresh sprouts aren't available, head to your frozen food section. Sprouts are one of the vegetables very highly rated to be just as good, if not better, frozen. (I LOVE the "Hanover" brand of frozen "Petite Brussel Sprouts". Always sweet & delicious.)
Fresh sprouts should be trimmed of any tough outside leaves, as well as any excess fiber at the root end. Depending on size, they can then be cooked whole or halved in boiling water for about 5-6 minutes tops, drained, then tossed with butter, salt, & better. After this treatment they can also be added to any basic cream or cheese sauce - alone or with other vegetables. Other prep possibilities are blanching & then roasting them with other fall vegetables, blanching & serving them on crudite platters, or blanching them, separating them into individual little leaves & serving them dressed as a warm fall salad. Cookbooks & websearchs will yield you hundreds of ways to use this versatile & good-for-you brassica.
Even if you've hated them for years, it would pay you to give them another try - without overcooking them.
Oh, and Brussel Sprouts come in both green & PURPLE/RED varieties. In fact, there are two red-purple varieties, both of which rarely if ever show up in markets. To enjoy those you have to grow them yourself, & seed is very easy to obtain. Like most brassicas, they need cool weather to perform at their best, & a frost sweetens them up nicely. In fact, I picked & enjoyed sprouts I grew myself well into early December - even with snow on the ground.