I just found a major snafu that has been there since probably around the time I started using Construct, as I found it way back in my backups from weeks ago. (I've only been using construct about 1-2 months). It was probably the result of me experimenting with Construct itself, before I had any idea how some features work.
The idea for this thread is to create a reference of silly mistakes that will probably help others, and will be a general source of amusement also.
Here are some of my bonehead mistakes:
Put the keyboard/mouse object as a container with another object. For months I thought it Construct was tying player control to the first created controllable object. I made all kinds of work arounds to keep that object alive so that keyboard controls would still be there on the next run. *facepalm*
(the problem here is that when the object is destroyed, the keyboard/mouse object is also destroyed due to the container behaviour - and hence no kb/m control).
Somehow managed to put random(50) into the initial value of a private variable. This crashed the hell out of Construct but ONLY after I'd uncovered and fixed another bug that was essentially suppressing this.
Inappropriate use of 'while's
Never use while, unless you ABSOLUTELY understand exactly what it does and why it's there.
Granted though, I was experimenting mostly but I found one in there that was eating a lot of CPU time and causing issues because I'd forgotten about it. Removing it had no effect on the behaviour of the items but freed up quite a bit of CPU time.
Post your own crazy Construct screwups.