This is probably a bug for windows XP - Vista - 7 operating systems.

So the bug:
1. Open launcher.
2. Launcher will pop up, but it will take tons of time.

This bug will occur more often if you have bad internet or restarted your computer like 10 minutes ago.

Workaround:
If checking/loading launcher took over 10 seconds for example, launcher will skip that

Development console:

Bootstrap started
Looking for update
At this part it will freeze
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma
Got reply in: 71820ms

Note the part it says 71820ms which means 71,8 seconds! Too much.