Exploded light bulb AND serious wiring question

Hello, experts!

As you already can guess my light bulb explode. It happen while switching on a table lamp with a 60 W incandescent light bulb. Usually I use LED bulbs but this was still working so yeah. And this isn't the first time this happened.
Sometimes it explodes and sometimes the light bulb stops working while still being very new.

So my three questions are:

1) Why did my light bulb explode?

2) Has it something to do with the wiring/extensions/too many socket connections?

3) And most importantly... is this safe to use electronics wired as you see in my image below?