My laptop is not exactly a screamer, but it's adequate for my purposes. I run Linux Mint 17 on it (Xfce desktop), which uses Thunar as its file manager. Not too long ago, I installed the RabbitVCS version control tools, including several plugins for Thunar needed to integrate the two.
Lately, Thunar has been incredibly slow to open (consistently approximately 20 seconds from click to window). The Web contains a variety of reports about Thunar being slow on first open, with several suggested fixes, but the fixes didn't apply in my case, and Thunar was slow for me every time, not just at first access. I tried opening it while running top in a terminal, but whatever was slowing down Thunar did not seem to be gobbling many CPU cycles.
So I uninstalled RabbitVCS and all associated plugins for Thunar, rebooted, and voila! Thunar now opens in under one second. As a side benefit, shutting down or rebooting the laptop, which previously suffered rather lengthy delays, is back to its normal speed.
I use RabbitVCS with the Nemo file manager on my PC (also Mint 17, but the Cinnamon desktop) with no problems, so the culprit is likely not RabbitVCS per se but rather something about the RabbitVCS - Thunar integration (?). Anyway, while I like RabbitVCS, I like having the laptop be responsive even more.