I remember my Atari behaving awfully slow (whole atari basic environment, even after the program finished) because I did many GOSUBs without the amount of RETUR

I remember my Atari behaving awfully slow (whole atari basic environment, even after the program finished) because I did many GOSUBs without the amount of RETURNs necessary, and didn't understand why because I was only 9yo at that time...