I don't like a saddle that I stick to. I want a saddle that I can easily slide forward and back on for the same reason I like to move my hand position around - you don't want any single part of your body compressed against something for a long time. Hands and behinds get sore easily if you don't.
If you feel like you're always sliding forward in your saddle, it needs to be tilted up more. For most riders I know on a Brooks B17, adjusted properly it looks like it's tilted up, but you're really just sitting in the depressed area in the middle.
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If someone tells you that you have enough bicycles and you don't need any more, stop talking to them. You don't need that kind of negativity in your life.