[De ce e dificil sa fii profitabil pe tf mici?!]

If there would be no commissions and you can just toss a coin to buy or sell then your chances on success would be 50/50. However, there is a spread commission and that's why you will have less winners than losers.

 

Further, If you trade with wide Take-profit/Stop-loss (100pips or more) then you would likely use H4 or Daily timeframes and so spread commission would look small comparing to your targets. If you continue to toss a coin, you'll have 49/51. On the other hand, if you use M5/M15 then you'll have to lower your Take-profit/Stop-loss to 20 pips so your spread now takes a big part of your trades. Tossing coins now bring much worse results, ~ 45/55.

 

Thereby, with a little strategy, you can win on H4/D1 because it's easier to shift your trading results from 49/51 to 55/45. Moreover, you'll have much stronger signals when you trade high TFs. However, if you continue to use M5/M15 then all you can do is to shift your chances from 45/55 to 50/50 and win back your spread. Signals on M5/M15 also very weak so it'll add problems.