Also, never let me near syrups...
I once tried making some absolutely delicious sounding chocolate syrup out of one of Alton Brown's books. It came out delicious, then I stuck it in a thin necked, glass bottle. I think it was a salad dressing bottle.
I put it in the fridge, and when I went to have some more later, it froze. I mean, it was a solid brown chunk stuck in a bottle where it was impossible to get to. O_o
My mum eventually helped me get it out (lots of warm water), but never again.
Of course, you think I would've learned from my first time...
I once heard of sugar syrup on Good Eats. I decided I would make some for some iced tea, because I have a real sweet tooth. I followed the directions, put it in a Pyrex glass cup and left in the fridge for later.
Went to retrieve it, and it also froze solid. I couldn't get it out except hours of work washing it, chipping it, hoping I could fix it before my parents would get home. Thankfully, they were away on a trip for a couple weeks.

Also, Dulce de Leche. Geeze, is Alton Brown a bad influence on me.

I love love love the stuff, and have gotten plenty of it canned before. Mum got the condensed milk for me, and let me try to make it while they were out for the day.
I followed the directions, only my mum said I could microwave it, so that is what I did. I was stirring it every couple of minutes while it went around the microwave, and around 15 minutes in to its 20 minute time, it started smoldering. Whoops.
I yanked it out and all was well, but no tastiness for me that day. Smelled like badly burnt sugar for a few days, though.