Playing / recording a mono synth instrument
It’s a little tricky to try and set down some licks on a mono synth. To your ear, it may come out nice and fine while playing. But when you look at the midi track it may look like crap. The problem is that the mono instrument doesn’t read when you accidentally hit two or more keys at once.
A good way to demonstrate this out is to try and play one line from a Bach invention which is only recording on that mono synth. Whenever keys rub, the midi looks like barf. Behold some barf, especially when ornaments are involved: