I always train alone at my gym =(
Did squats last night also, just regular squats but I got stuck at parallel on my 7th rep of 8rep set, just stayed there for like 5 seconds trying to imagine it was live or die or that it was a car trapped on top of someone and they'd die if I didn't lift it. None of that helped and I had to use the safety bars, really was not good as I had to remove some weights and get it back on the rack and then add some weights again =(
Whenever I see anyone who looks like they seriously work out and they are lifting a light weight I always take it that it's a warm up or a big set, regardless I never judge anyone on what they lift anyway so don't worry about anyone thinking you were weak. Here's a paragraph of an article which I always remember when I am lifting light (i.e. warm ups, big sets or starting at a light weight on an exercise) and people watch me...
"Okay, so you like to work chest first before back. Sure, if you work your back first, you won't be able to use as much weight on bench press because you'll be tired. The big guys and the cute girls will see you using 20 pounds less and wham! There goes your credibility. They'll no longer hold the door open for you; no longer pick up your tab at the Blubber Butt Buffet; forget about letting you take cuts in front of them at the movie theater… what's that? They didn't do any of those things anyhow? Oh. Well then, what are you worried about?"