http://www.investopedia.com/articles/technical/061801.asp

The concept of support and resistance is separate from trend lines. The idea is this, say the market is going down, and it finds some support at a price, because there are a lot of people buying at that price. Now if the market surpasses this price and continues further down, but then eventually turns around, when it retraces back to the previous support, it now becomes resistance, because at that point a lot of people longs, and now that it has got back to their buy in on their bad play, they're happy to get out at break even and so you have added sell pressure at that point.

And the reason behind this is the same reason that you can't call diagonal trendlines support/resistance, because it shows a true misunderstanding of what support/resistance actually is, and what causes it.

It's kind of absurd that this even needs to be explained in a trading sub, this is literally trading 101. If anyone here actually bothered to read just a modicum of information about trading before going full retard with leverage, they might actually not just lose all their money.