Someone tell me how to solve this – Linearity Curve Graphic Design Review

Soooooo ummmm......IT KEEPS AUTO CORRECTING MEH LINES! WHEN I TRY TO DRAW A ZIG ZAG IT TURNED INTO CURVES! Someone pls help meh *･゜ﾟ･*:.｡..｡.:*･'(*ﾟ▽ﾟ*)'･*:.｡. .｡.:*･゜ﾟ･*
Review by anime shiper on Linearity Curve Graphic Design.